Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STATEMENT TO NOTEHOLDERS

May 12, 2025


TRANSACTION PARTIES


Depositor:	Citigroup Commercial Mortgage Securities Inc.
Master Servicer:	Wells Fargo Bank, National Association
Certificate Administrator:	Citibank, N.A.
Trustee:	Deutsche Bank Trust Company Americas
Special Servicer:	Torchlight Loan Services, LLC
Operating Advisor:	Pentalpha Surveillance LLC.




	Danny Lee	Citibank, Agency and Trust
	(212) 816-4936	388 Greenwich Street Trading, 4th Floor
danny1.lee@citi.com		New York, NY 10013


TABLE OF CONTENTS


1	.	Distribution Summary	2
1.1	.	Summary	2
1.2	.	Factors	3
2	.	Distribution Detail	4
2.1	.	Interest Detail	4
2.2	.	Interest Shortfall Detail	5
2.3	.	Principal Detail	6
3	.	Reconciliation Detail	7
4	.	Other Information	8
5	.	Stratification Detail	9
6	.	Mortgage Loan Detail	14
7	.	NOI Detail	16
8	.	Delinquency Loan Detail	17
9	.	Collateral Performance Delinquency and Loan Status Detail	18
10	.	Appraisal Reduction Detail	19
11	.	Historical Appraisal Reduction Detail	20
12	.	Loan Modification Detail	22
13	.	Historical Loan Modification Detail	23
14	.	Specially Serviced Loan Detail	25
15	.	Historical Specially Serviced Loan Detail	26
16	.	Unscheduled Principal Detail	31
17	.	Historical Unscheduled Principal Detail	32
18	.	Liquidated Loan Detail	33
19	.	Historical Liquidated Loan Detail	34
20	.	CREFC Investor Reporting Package Legends	35
21	.	Notes	36


Reports Available at sf.citidirect.com	v. 21.09.28	Page 1 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DISTRIBUTION SUMMARY

May 12, 2025


					Accrual		Other				Non-Cash
	Original	Prior	Pass-Through		Day	Interest	(As Interest)	Principal	Total	Realized Loss	Balance		Current
Class	Balance	Balance	Rate		Count	Distributed	Distributed	Distributed	Distributed	/(Recovery)	Change		Balance

Class A-1	28,330,000.00	-	1.637000	%	30/360	-	-	-	-	-	-		-
Class A-2	2,298,000.00	-	3.084000	%	30/360	-	-	-	-	-	-		-
Class A-3	160,000,000.00	-	3.497000	%	30/360	-	-	-	-	-	-		-
Class A-4	268,724,000.00	265,768,873.31	3.762000	%	30/360	833,185.42	-	67,307,197.48	68,140,382.90	-	-		198,461,675.83
Class A-AB	46,974,000.00	-	3.431000	%	30/360	-	-	-	-	-	-		-
Class A-S	58,763,000.00	58,763,000.00	3.941848	%	30/360	193,029.03	-	-	193,029.03	-	-		58,763,000.00
Class B	42,871,000.00	42,871,000.00	3.942848	%	30/360	140,861.54	-	-	140,861.54	-	-		42,871,000.00
Class C	33,852,000.00	33,852,000.00	3.942848	%	30/360	9,428.70	-	-	9,428.70	-	-		33,852,000.00
Class D	24,284,000.00	24,284,000.00	3.942848	%	30/360	-	-	-	-	-	-		24,284,000.00
Class E	11,000,000.00	11,000,000.00	3.942848	%	30/360	-	-	-	-	-	-		11,000,000.00
Class F	14,864,000.00	14,864,000.00	3.942848	%	30/360	-	-	-	-	4,024,179.89	-		10,839,820.11
Class G	12,231,000.00	12,231,000.00	3.942848	%	30/360	-	-	-	-	12,231,000.00	-		-
Class H	19,132,869.00	4,534,830.12	3.942848	%	30/360	-	-	-	-	4,534,830.12	-		-
Class S	-	-	0.000000	%	30/360	-	-	-	-	-	-		-
Class R	-	-	0.000000	%	30/360	-	-	-	-	-	-		-
Total	723,323,869.00	468,168,703.43				1,176,504.69	-	67,307,197.48	68,483,702.17	20,790,010.01	-		380,071,495.94
Notional
Class X-A	565,089,000.00	324,531,873.31	0.148283	%	30/360	40,102.19	-	-	40,102.19	-	(67,307,197.48	)	257,224,675.83

Grand Total	1,288,412,869.00	792,700,576.74				1,216,606.88	-	67,307,197.48	68,523,804.36	20,790,010.01	(67,307,197.48	)	637,296,171.77


Reports Available at sf.citidirect.com	v. 21.09.28	Page 2 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DISTRIBUTION SUMMARY - FACTORS

May 12, 2025


					Other				Non-Cash
			Record	Interest	(As Interest)	Principal	Total	Realized Loss	Balance	Current
Class	CUSIP		Date	Distributed	Distributed	Distributed	Distributed	/(Recovery)	Change	Balance

Class A-1	17323	YAA7	04/30/2025	-	-	-	-	-	-	-
Class A-2	17323	YAB5	04/30/2025	-	-	-	-	-	-	-
Class A-3	17323	YAC3	04/30/2025	-	-	-	-	-	-	-
Class A-4	17323	YAD1	04/30/2025	3.10052478	-	250.46961745	253.57014223	-	-	738.53349842
Class A-AB	17323	YAE9	04/30/2025	-	-	-	-	-	-	-
Class A-S	17323	YAF6	04/30/2025	3.28487364	-	-	3.28487364	-	-	1,000.00000000
Class X-A	17323	YAL3	04/30/2025	0.07096615	-	-	0.07096615	-	-	455.19320997
Class B	17323	YAG4	04/30/2025	3.28570689	-	-	3.28570689	-	-	1,000.00000000
Class C	17323	YAH2	04/30/2025	0.27852712	-	-	0.27852712	-	-	1,000.00000000
Class D	17323	YAJ8	04/30/2025	-	-	-	-	-	-	1,000.00000000
Class E	17323	YAN9	04/30/2025	-	-	-	-	-	-	1,000.00000000
Class F	17323	YAQ2	04/30/2025	-	-	-	-	270.73330799	-	729.26669201
Class G	17323	YAS8	04/30/2025	-	-	-	-	1,000.00000000	-	-
Class H	17323	YAU3	04/30/2025	-	-	-	-	237.01777919	-	-
Class S	17323	YAW9	04/30/2025	-	-	-	-	-	-	-
Class R	17323	YAY5	04/30/2025	-	-	-	-	-	-	-


Reports Available at sf.citidirect.com	v. 21.09.28	Page 3 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DISTRIBUTION INFORMATION - INTEREST DETAIL

May 12, 2025


			Rate					Interest			Shortfall				Paid
															Cap
							Accrual	Net	Accreted	Non	Carry	Cap Carryover			Carryover
Class	Uncapped Capped				Next		Dates	Accrued	/Deferred	Recovered	Forward	/Basis Risk	Accrued	Carry Forward /Basis Risk		Total

Class A-1	1.63700	%	1.63700	%	1.63700	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Class A-2	3.08400	%	3.08400	%	3.08400	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Class A-3	3.49700	%	3.49700	%	3.49700	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Class A-4	3.76200	%	3.76200	%	3.76200	%	04/01-04/30	833,185.42	-	-	-	-	833,185.42	-	-	833,185.42
Class A-AB	3.43100	%	3.43100	%	3.43100	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Class A-S	3.94185	%	3.94185	%	3.94185	%	04/01-04/30	193,029.03	-	-	-	-	193,029.03	-	-	193,029.03
Class B	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	140,861.54	-	-	-	-	140,861.54	-	-	140,861.54
Class C	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	111,227.75	-	-	103,291.88	-	9,428.70	-	-	9,428.70
Class D	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	79,790.11	-	-	83,413.53	-	-	-	-	-
Class E	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	36,142.78	-	-	37,903.51	-	-	-	-	-
Class F	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	48,838.75	-	-	51,228.94	-	-	-	-	-
Class G	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	40,187.48	-	-	43,873.65	-	-	-	-	-
Class H	3.94285	%	3.94285	%	3.94285	%	04/01-04/30	14,900.12	-	-	22,350.82	-	-	-	-	-
Class S	0.00000	%	0.00000	%	0.00000	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Class R	0.00000	%	0.00000	%	0.00000	%	04/01-04/30	-	-	-	-	-	-	-	-	-
Total								1,498,162.98	-	-	342,062.33	-	1,176,504.69	-	-	1,176,504.69
Notional
Class X-A	0.14828	%	0.14828	%	0.14828	%	04/01-04/30	40,102.19	-	-	-	-	40,102.19	-	-	40,102.19
Total								40,102.19	-	-	-	-	40,102.19	-	-	40,102.19

Grand Total								1,538,265.17	-	-	342,062.33	-	1,216,606.88	-	-	1,216,606.88


Reports Available at sf.citidirect.com	v. 21.09.28	Page 4 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DISTRIBUTION INFORMATION - INTEREST SHORTFALL DETAIL

May 12, 2025


											Cap Carryover /
	Non-Recov Shortfall				Carry Forward Interest					Basis Risk Shortfall
			Other
Class	PPIS	SSRA	Shortfall	Prior	Int. on Prior	New	Paid	Outstanding	Prior	Int. on Prior	New	Paid	Outstanding

Class A-1	-	-	-	-	-	-	-	-	-	-	-	-	-
Class A-2	-	-	-	-	-	-	-	-	-	-	-	-	-
Class A-3	-	-	-	-	-	-	-	-	-	-	-	-	-
Class A-4	-	-	-	-	-	-	-	-	-	-	-	-	-
Class A-AB	-	-	-	-	-	-	-	-	-	-	-	-	-
Class A-S	-	-	-	-	-	-	-	-	-	-	-	-	-
Class B	-	-	-	-	-	-	-	-	-	-	-	-	-
Class C	-	-	-	454,341.03	1,492.83	101,799.05	-	557,632.91	-	-	-	-	-
Class D	-	-	-	1,102,783.06	3,623.42	79,790.11	-	1,186,196.59	-	-	-	-	-
Class E	-	-	-	535,876.52	1,760.73	36,142.78	-	573,780.03	-	-	-	-	-
Class F	-	-	-	727,450.55	2,390.19	48,838.75	-	778,679.49	-	-	-	-	-
Class G	-	-	-	1,121,879.16	3,686.17	40,187.48	-	1,165,752.81	-	-	-	-	-
Class H	-	-	-	2,267,609.81	7,450.70	14,900.12	-	2,289,960.63	-	-	-	-	-
Class S	-	-	-	-	-	-	-	-	-	-	-	-	-
Class R	-	-	-	-	-	-	-	-	-	-	-	-	-
Total	-	-	-	6,209,940.13	20,404.04	321,658.29	-	6,552,002.46	-	-	-	-	-
Notional
Class X-A	-	-	-	-	-	-	-	-	-	-	-	-	-
Total	-	-	-	-	-	-	-	-	-	-	-	-	-

Grand Total	-	-	-	6,209,940.13	20,404.04	321,658.29	-	6,552,002.46	-	-	-	-	-


Reports Available at sf.citidirect.com	v. 21.09.28	Page 5 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DISTRIBUTION INFORMATION - PRINCIPAL DETAIL

May 12, 2025


					Non-Cash		Cumulative
	Prior	Principal	Accreted	Realized Loss	Balance	Current	Realized	Class %		Class %		Sub %		Sub %
Class	Balance	Distributed	Principal	/(Recovery)	Change	Balance	Loss	Original		Current		Original		Current

Class A-1	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%
Class A-2	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%
Class A-3	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%
Class A-4	265,768,873.31	67,307,197.48	-	-	-	198,461,675.83	-	0.00	%	0.00	%	0.00	%	0.00	%
Class A-AB	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%
Class A-S	58,763,000.00	-	-	-	-	58,763,000.00	-	0.00	%	0.00	%	0.00	%	0.00	%
Class B	42,871,000.00	-	-	-	-	42,871,000.00	-	0.00	%	0.00	%	0.00	%	0.00	%
Class C	33,852,000.00	-	-	-	-	33,852,000.00	-	0.00	%	0.00	%	0.00	%	0.00	%
Class D	24,284,000.00	-	-	-	-	24,284,000.00	-	0.00	%	0.00	%	0.00	%	0.00	%
Class E	11,000,000.00	-	-	-	-	11,000,000.00	-	0.00	%	0.00	%	0.00	%	0.00	%
Class F	14,864,000.00	-	-	4,024,179.89	-	10,839,820.11	4,024,179.89	0.00	%	0.00	%	0.00	%	0.00	%
Class G	12,231,000.00	-	-	12,231,000.00	-	-	12,231,000.00	0.00	%	0.00	%	0.00	%	0.00	%
Class H	4,534,830.12	-	-	4,534,830.12	-	-	19,132,869.00	0.00	%	0.00	%	0.00	%	0.00	%
Class S	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%
Class R	-	-	-	-	-	-	-	0.00	%	0.00	%	0.00	%	0.00	%

Total	468,168,703.43	67,307,197.48	-	20,790,010.01	-	380,071,495.94	35,388,048.89	0.00	%	0.00	%


Reports Available at sf.citidirect.com	v. 21.09.28	Page 6 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

RECONCILIATION DETAIL

May 12, 2025


SOURCE OF FUNDS			ALLOCATION OF FUNDS

Interest Funds Available			Scheduled Fees
Scheduled Interest	1,270,066.97		Servicing Fee	3,939.73
Prepayment Interest Shortfall	-		Trustee/Certificate Administrator Fee	1,326.49
Interest Adjustments	-		Operating Advisor Fee	507.18
ASER Amount	-		CREFC Intellectual Property Royalty License Fee	195.07
Realized Loss in Excess of Principal Balance	-
			Total Scheduled Fees		5,968.47
Total Interest Funds Available		1,270,066.97	Additional Fees, Expenses, etc.
Principal Funds Available			Additional Servicing Fee	-
Scheduled Principal	586,100.46		Special Servicing Fee	47,491.62
Unscheduled Principal Collections	87,511,107.03		Work-out Fee	-
Repurchased Principal	-		Liquidation Fee	-
Substitution Principal	-		Trust Fund Expenses	-
Other Principal	-		Trust Advisor Expenses	-
			Reimbursement of Interest on Advances to the Servicer	-
Total Principal Funds Available		88,097,207.49
			Borrower Reimbursable Trust Fund Expenses	-
Other Funds Available
			Reimbursement of Nonrecoverable Advances to the Servicer	20,790,010.01
Yield Maintenance Charges	-
			Other Expenses	-
Withdrawal of Withheld Amounts from the Interest Reserve
Account	-		Total Additional Fees, Expenses, etc.		20,837,501.63
Deposit of Withheld Amounts to the Interest Reserve Account	-
			Distributions
Current Period Adjustment to Loan - Other	-
			Interest Distribution	1,216,606.88
Total Other Funds Available		-	Principal Distribution	67,307,197.48
			Yield Maintenance Charge Distribution	-
			Total Distributions		68,523,804.36




Total Funds Available		89,367,274.46
			Total Funds Allocated		89,367,274.46


Reports Available at sf.citidirect.com	v. 21.09.28	Page 7 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

OTHER INFORMATION

Interest Reserve Account Information

May 12, 2025


Beginning Interest Reserve Account Balance	0.00
Deposit of Withheld Amounts to the Interest Reserve Account	0.00
Withdrawal of Withheld Amounts from the Interest Reserve Account	0.00
Ending Interest Reserve Account Balance	0.00
Excess Liquidation Proceeds Reserve Account Information
Beginning Excess Liquidation Proceeds Reserve Account Balance	0.00
Deposit to the Excess Liquidation Proceeds Reserve Account	0.00
Withdrawal from the Excess Liquidation Proceeds Reserve Account	0.00
Ending Excess Liquidation Proceeds Reserve Account Balance	0.00
Collateral Information
% of Cut-Off Principal Balance Outstanding	52.545134	%
Controlling Class Information
Controlling Class is Class F.
Control Termination Event is in Effect.
Identification of the current Controlling Class Representative has not been provided.
There Are No Disclosable Special Servicer Fees.
Non-Active Exchangeable Certificates
Class PEZ Beginning Balance	135,486,000.00
Class PEZ Ending Balance	135,486,000.00


Reports Available at sf.citidirect.com	v. 21.09.28	Page 8 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STRATIFICATION DETAIL

May 12, 2025


Anticipated Remaining Term

Anticipated Remaining	Asset	Ending Scheduled	% of			Wtd Avg
Term Range	Count	Balance	Agg.Bal. WAC		WAM	DSCR

60 Months or Less	35	380,071,495.94	100.00	3.9195	16	0.658931
61 to 90 Months	0	0.00	0.00	0.0000	0	0.000000
91 Months or Greater	0	0.00	0.00	0.0000	0	0.000000
Total	35	380,071,495.94	100.00	3.9195	16	0.658931

Debt Service Coverage Ratio

Debt Service Coverage	Asset	Ending Scheduled	% of			Wtd Avg
Ratio Range	Count	Balance	Agg.Bal. WAC		WAM	DSCR

1.250 or Less	10	187,896,698.82	49.44	3.7558	32	-0.907803
1.251 to 1.500	3	9,312,821.27	2.45	4.4100	1	1.448300
1.501 to 1.750	4	24,374,898.62	6.41	4.1681	1	1.535857
1.751 to 2.000	6	84,370,633.49	22.20	3.9740	0	1.856898
2.001 to 2.250	3	11,700,272.06	3.08	4.2456	0	2.080332
2.251 to 2.500	3	13,989,852.84	3.68	4.3840	1	2.306158
2.501 to 2.750	3	34,883,717.02	9.18	4.0619	1	2.560661
2.751 to 3.000	1	0.00	0.00	0.0000	0	0.000000
3.001 to 3.250	0	0.00	0.00	0.0000	0	0.000000
3.251 to 3.500	0	0.00	0.00	0.0000	0	0.000000
3.501 to 3.750	1	4,542,601.82	1.20	3.9570	1	3.742900
3.751 to 4.000	0	0.00	0.00	0.0000	0	0.000000
4.001 or Greater	1	9,000,000.00	2.37	3.9300	1	5.610100
Total	35	380,071,495.94	100.00	3.9195	16	0.658931


Reports Available at sf.citidirect.com	v. 21.09.28	Page 9 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STRATIFICATION DETAIL

May 12, 2025


Ending Schedule Balance

Ending Schedule Balance	Asset	Ending Scheduled	% of			Wtd Avg
Range	Count	Balance	Agg.Bal. WAC WAM			DSCR

1 to 5,000,000	10	32,329,643.80	8.51	4.4253	0	2.164763
10,000,001 to 15,000,000	2	25,411,510.61	6.69	4.4988	1	1.136513
15,000,001 to 20,000,000	1	19,221,986.18	5.06	4.1065	1	1.505900
20,000,001 to 25,000,000	2	42,933,308.71	11.30	4.0835	1	1.915090
25,000,001 to 30,000,000	0	0.00	0.00	0.0000	0	0.000000
30,000,001 to 35,000,000	0	0.00	0.00	0.0000	0	0.000000
35,000,001 to 40,000,000	1	39,090,877.72	10.29	4.1300	1	1.189400
40,000,001 to 45,000,000	0	0.00	0.00	0.0000	0	0.000000
45,000,001 to 50,000,000	0	0.00	0.00	0.0000	0	0.000000
5,000,001 to 10,000,000	7	49,084,168.92	12.91	4.1905	1	2.730492
50,000,001 to 55,000,000	0	0.00	0.00	0.0000	0	0.000000
55,000,001 to 60,000,000	0	0.00	0.00	0.0000	0	0.000000
60,000,001 to 65,000,000	0	0.00	0.00	0.0000	0	0.000000
65,000,001 to 70,000,000	0	0.00	0.00	0.0000	0	0.000000
70,000,001 to 75,000,000	1	72,000,000.00	18.94	3.9085	0	1.866500
75,000,001 to 80,000,000	0	0.00	0.00	0.0000	0	0.000000
80,000,001 to 85,000,000	0	0.00	0.00	0.0000	0	0.000000
85,000,000+	1	100,000,000.00	26.31	3.2950	60	-2.745000
Total	35	380,071,495.94	100.00	3.9195	16	0.658931


Reports Available at sf.citidirect.com	v. 21.09.28	Page 10 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STRATIFICATION DETAIL

May 12, 2025


Loan Rate

	Asset	Ending Scheduled	% of			Wtd Avg
Loan Rate Range	Count	Balance	Agg.Bal. WAC WAM			DSCR

4.00 or Less	11	214,898,139.70	56.54	3.6255	28	-0.005406
4.01 to 4.25	5	69,244,956.65	18.22	4.1342	1	1.418402
4.26 to 4.50	15	75,683,924.34	19.91	4.3698	1	1.640525
4.51 to 4.75	4	20,244,475.25	5.33	4.6220	0	1.443552
4.76 to 5.00	0	0.00	0.00	0.0000	0	0.000000
5.01 to 5.25	0	0.00	0.00	0.0000	0	0.000000
5.26 to 5.50	0	0.00	0.00	0.0000	0	0.000000
5.51 to 5.75	0	0.00	0.00	0.0000	0	0.000000
5.76 to 6.00	0	0.00	0.00	0.0000	0	0.000000
6.01 to 6.25	0	0.00	0.00	0.0000	0	0.000000
6.26 to 6.50	0	0.00	0.00	0.0000	0	0.000000
6.51 to 6.75	0	0.00	0.00	0.0000	0	0.000000
6.76 to 7.00	0	0.00	0.00	0.0000	0	0.000000
7.01 or Greater	0	0.00	0.00	0.0000	0	0.000000
Total	35	380,071,495.94	100.00	3.9195	16	0.658931

Property Type

	Asset	Ending Scheduled	% of			Wtd Avg
Property Type Range	Count	Balance	Agg.Bal. WAC WAM			DSCR

Industrial	0	0.00	0.00	0.0000	0	0.000000
Lodging	2	11,799,802.06	3.10	4.3889	1	1.470789
Mixed Use	3	43,133,516.54	11.35	4.2302	1	1.391920
Multifamily	6	9,413,463.33	2.48	4.4712	1	2.401228
Office	5	149,466,706.78	39.33	3.5698	40	-1.377516
Other	7	93,470,004.85	24.59	4.0022	0	1.855920
Retail	10	61,122,070.73	16.08	4.2273	0	2.090076
Self Storage	2	11,665,931.65	3.07	4.0557	1	4.724323
Total	35	380,071,495.94	100.00	3.9195	16	0.658931


Reports Available at sf.citidirect.com	v. 21.09.28	Page 11 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STRATIFICATION DETAIL

May 12, 2025


Remaining Amortization Term

Remaining Amortization	Asset	Ending Scheduled	% of			Wtd Avg
Term Range	Count	Balance	Agg.Bal.	WAC	WAM	DSCR

240 Months or Less	8	216,028,515.38	56.84	3.6503	27	-0.051426
241 to 270 Months	27	164,042,980.56	43.16	4.2740	0	1.594400
271 to 300 Months	0	0.00	0.00	0.0000	0	0.000000
301 Months or Greater	0	0.00	0.00	0.0000	0	0.000000
Total	35	380,071,495.94	100.00	3.9195	16	0.658931

Seasoning

	Asset	Ending Scheduled	% of			Wtd Avg
Seasoning Range	Count	Balance	Agg.Bal.	WAC	WAM	DSCR

12 Months or Less	0	0.00	0.00	0.0000	0	0.000000
13 to 24 Months	0	0.00	0.00	0.0000	0	0.000000
25 to 36 Months	0	0.00	0.00	0.0000	0	0.000000
37 to 48 Months	0	0.00	0.00	0.0000	0	0.000000
49 Months or Greater	35	380,071,495.94	100.00	3.9195	16	0.658931
Total	35	380,071,495.94	100.00	3.9195	16	0.658931


Reports Available at sf.citidirect.com	v. 21.09.28	Page 12 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

STRATIFICATION DETAIL

May 12, 2025


State

	Asset	Ending Scheduled	% of			Wtd Avg
State Range	Count	Balance	Agg.Bal. WAC WAM			DSCR

California	3	82,024,186.43	21.58	4.1057	1	1.569243
Colorado	1	2,486,980.79	0.65	4.3100	1	1.555000
Florida	4	25,003,990.73	6.58	4.3699	1	1.454431
Hawaii	1	9,000,000.00	2.37	3.9300	1	5.610100
Illinois	1	100,000,000.00	26.31	3.2950	60	-2.745000
Iowa	0	0.00	0.00	0.0000	0	0.000000
Kansas	1	4,992,468.91	1.31	4.4900	1	2.317200
Louisiana	1	0.00	0.00	0.0000	0	0.000000
Maryland	1	0.00	0.00	0.0000	0	0.000000
Michigan	2	10,108,221.70	2.66	4.4055	1	2.444457
Minnesota	0	0.00	0.00	0.0000	0	0.000000
Nebraska	1	9,312,821.27	2.45	4.4100	1	1.448300
Nevada	0	0.00	0.00	0.0000	0	0.000000
New Jersey	0	0.00	0.00	0.0000	0	0.000000
North Carolina	1	0.00	0.00	0.0000	0	0.000000
Ohio	1	2,019,201.37	0.53	4.7000	0	2.146000
Oklahoma	2	0.00	0.00	0.0000	0	0.000000
Oregon	0	0.00	0.00	0.0000	0	0.000000
Pennsylvania	1	5,795,786.50	1.52	4.3000	1	2.635000
Rhode Island	1	5,155,000.00	1.36	4.1400	1	1.841700
South Carolina	1	2,525,532.81	0.66	4.7200	1	2.101300
Texas	5	28,177,300.58	7.41	4.1984	1	1.698383
Various	7	93,470,004.85	24.59	4.0022	0	1.855920
Total	35	380,071,495.94	100.00	3.9195	16	0.658931


Reports Available at sf.citidirect.com	v. 21.09.28	Page 13 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

MORTGAGE LOAN DETAIL

May 12, 2025


		Prop			Paid					Beginning	Ending		Payment Workout Mod
		Type			Through	Gross		Interest	Principal	Scheduled	Scheduled	Maturity	Status		Strategy Code
Loan ID	OMCR	(1)	City	State	Date	Coupon		Payment	Payment	Balance	Balance	Date	(2	)	(3	)	(4	)

304101385	1	OF	Chicago	IL	10/06/2021	3.29500	%	-	-	100,000,000.00	100,000,000.00	05/06/2030	3		1		0
304140010	10	RT	San Diego	CA	05/06/2025	3.90100	%	72,168.50	-	22,200,000.00	22,200,000.00	06/06/2025	0		0		0
304101390	12	N/A	Various	Various	05/06/2025	4.42000	%	47,581.92	28,178.14	12,918,169.33	12,889,991.19	06/06/2025	0		0		0
300571323	13	RT	Port Charlotte	FL	03/06/2025	4.58000	%	47,892.67	26,779.00	12,548,298.42	12,521,519.42	06/06/2025	1		0		0
304140014	14	RT	Hagerstown	MD	05/06/2025	3.99700	%	37,674.38	11,310,797.69	11,310,797.69	-	05/06/2025	0		0		0
304101380	15	N/A	Various	Various	05/06/2025	3.95000	%	32,718.72	9,939,864.93	9,939,864.93	-	05/06/2025	0		0		0
304101397	17	LO	Omaha	NE	05/06/2025	4.41000	%	34,304.90	21,846.50	9,334,667.77	9,312,821.27	06/06/2025	0		8		8
304140002	2	N/A	Various	Various	04/06/2025	3.90850	%	234,510.00	-	72,000,000.00	72,000,000.00	04/06/2025	5		0		0
304101399	20	SS	Kaneohe	HI	05/06/2025	3.93000	%	29,475.00	-	9,000,000.00	9,000,000.00	06/06/2025	0		0		0
304101389	22	OF	Coral Gables	FL	05/06/2025	3.95000	%	23,616.49	19,091.86	7,174,629.74	7,155,537.88	06/06/2025	0		0		0
304101398	23	MF	DeWitt	MI	05/06/2025	4.38000	%	25,192.59	14,149.35	6,902,079.87	6,887,930.52	06/06/2025	0		0		0
304140024	24	RT	Shippensburg	PA	05/01/2025	4.30000	%	20,821.30	14,809.44	5,810,595.94	5,795,786.50	06/01/2025	0		0		0
304101391	25	RT	Houston	TX	05/06/2025	4.25000	%	20,503.35	12,087.67	5,789,180.42	5,777,092.75	06/06/2025	0		0		0
304140027	27	MF	Stillwater	OK	05/06/2025	4.30000	%	19,220.56	5,363,878.20	5,363,878.20	-	05/06/2025	0		0		0
300571332	31	RT	Overland Park	KS	05/06/2025	4.49000	%	18,720.60	10,809.83	5,003,278.74	4,992,468.91	06/06/2025	0		0		0
304140034	34	RT	North Smithfield	RI	04/01/2025	4.14000	%	17,784.75	-	5,155,000.00	5,155,000.00	06/01/2025	B		13		0
304140035	35	N/A	Various	Various	05/06/2025	3.95700	%	15,008.05	8,738.93	4,551,340.75	4,542,601.82	06/06/2025	0		0		0
301461015	36	N/A	Various	Various	05/06/2025	4.39000	%	14,807.52	10,201.00	4,047,612.84	4,037,411.84	06/06/2025	0		0		0
304140038	38	MF	Kingsville	TX	05/06/2025	4.30000	%	14,339.15	4,001,623.16	4,001,623.16	-	05/06/2025	0		0		0
304140039	39	RT	Winston-Salem	NC	05/06/2025	4.40000	%	13,419.38	3,659,832.18	3,659,832.18	-	05/06/2025	0		0		0
304101400	4	OF	Pasadena	CA	04/06/2025	4.13000	%	134,774.90	68,900.01	39,159,777.73	39,090,877.72	06/06/2025	B		13		0
304101396	40	RT	Tallahassee	FL	05/06/2025	4.40000	%	9,819.90	17,152.46	2,678,154.24	2,661,001.78	06/06/2025	0		0		0
304140041	41	MU	Mesquite	TX	05/01/2025	4.66000	%	12,372.23	7,760.99	3,185,982.64	3,178,221.65	06/01/2025	0		0		0
304101386	42	N/A	Various	Various	05/06/2025	4.15000	%	10,525.01	3,043,375.61	3,043,375.61	-	05/06/2025	0		0		0
304101387	43	OF	Ann Arbor	MI	05/06/2025	4.46000	%	11,993.06	6,540.38	3,226,831.56	3,220,291.18	06/06/2025	0		0		0
304140045	45	MF	North Charleston	SC	05/01/2025	4.72000	%	9,970.56	9,354.81	2,534,887.62	2,525,532.81	06/01/2025	0		0		0
304101407	46	LO	Eagle	CO	05/06/2025	4.31000	%	8,966.77	9,566.74	2,496,547.53	2,486,980.79	06/06/2025	0		0		0
300571326	47	SS	Eustis	FL	05/06/2025	4.48000	%	9,975.96	6,199.96	2,672,131.61	2,665,931.65	06/06/2025	0		0		0
304101388	49	RT	Dover	OH	04/06/2025	4.70000	%	7,927.86	4,934.36	2,024,135.73	2,019,201.37	05/06/2025	5		8		0
304140005	5	OF	Oklahoma City	OK	05/01/2025	3.93500	%	80,559.76	24,567,142.69	24,567,142.69	-	05/01/2025	0		0		0
304101392	6	N/A	Various	Various	05/06/2025	4.34000	%	93,424.87	25,831,760.14	25,831,760.14	-	06/06/2025	0		0		0
304140008	8	MU	Orinda	CA	05/06/2025	4.27900	%	74,066.99	37,989.09	20,771,297.80	20,733,308.71	06/06/2025	0		0		0


Reports Available at sf.citidirect.com	v. 21.09.28	Page 14 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

MORTGAGE LOAN DETAIL

May 12, 2025

Prop

Paid

Beginning

Ending

Payment

Workout

Mod

Type

Through

Gross

Interest

Principal

Scheduled

Maturity

Status

Strategy

Code

Loan ID

OMCR

)

City

State

Date

Coupon

Payment

Balance

Date

)

304140009

Sugar Land

05/06/2025

4.10650

65,929.27

43,842.37

19,265,828.55

19,221,986.18

06/06/2025

Total

Count = 33

1,270,066.97

88,097,207.49

468,168,703.43

380,071,495.94


Reports Available at sf.citidirect.com	v. 21.09.28	Page 15 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

NOI DETAIL

May 12, 2025


		Property			Ending	Preceding		Most		Most Recent	Most Recent
		Type			Scheduled	Fiscal		Recent		Financial As of	Financial Asof
Loan ID	OMCR	(1)	City	State	Balance	Year NOI		NOI		Start Date	End Date

304101385	1	OF	Chicago	IL	100,000,000.00	(6,284,037.54	)	(1,938,134.55	)	01/01/2025	03/31/2025
304140010	10	RT	San Diego	CA	22,200,000.00	2,561,389.00		1,790,355.21		Not Available	Not Available
304101390	12	N/A	Various	Various	12,889,991.19	1,064,987.56		798,741.16		Not Available	Not Available
300571323	13	RT	Port Charlotte	FL	12,521,519.42	1,445,498.01		878,629.53		Not Available	Not Available
304101397	17	LO	Omaha	NE	9,312,821.27	1,222,754.56		1,242,509.64		04/01/2024	03/31/2025
304140002	2	N/A	Various	Various	72,000,000.00	27,939,961.01		14,683,458.00		Not Available	Not Available
304101399	20	SS	Kaneohe	HI	9,000,000.00	1,978,039.76		1,521,503.26		Not Available	Not Available
304101389	22	OF	Coral Gables	FL	7,155,537.88	956,722.97		977,698.32		01/01/2024	09/30/2024
304101398	23	MF	DeWitt	MI	6,887,930.52	903,337.00		692,632.00		Not Available	Not Available
304140024	24	RT	Shippensburg	PA	5,795,786.50	1,197,635.60		909,266.35		Not Available	Not Available
304101391	25	RT	Houston	TX	5,777,092.75	741,354.90		233,005.04		01/01/2025	03/31/2025
300571332	31	RT	Overland Park	KS	4,992,468.91	650,730.00		221,493.30		01/01/2025	03/31/2025
304140034	34	RT	North Smithfield	RI	5,155,000.00	401,800.00		200,900.00		01/01/2020	06/30/2020
304140035	35	N/A	Various	Various	4,542,601.82	1,125,069.12		831,016.71		Not Available	Not Available
301461015	36	N/A	Various	Various	4,037,411.84	525,700.09		137,835.53		Not Available	Not Available
304101400	4	OF	Pasadena	CA	39,090,877.72	2,900,108.60		2,334,548.00		Not Available	Not Available
304101396	40	RT	Tallahassee	FL	2,661,001.78	423,466.98		187,757.56		Not Available	Not Available
304140041	41	MU	Mesquite	TX	3,178,221.65	483,574.65		369,104.94		Not Available	Not Available
304101387	43	OF	Ann Arbor	MI	3,220,291.18	515,443.50		140,103.67		01/01/2025	03/31/2025
304140045	45	MF	North Charleston	SC	2,525,532.81	482,814.00		264,209.00		Not Available	Not Available
304101407	46	LO	Eagle	CO	2,486,980.79	428,154.00		394,103.00		Not Available	Not Available
300571326	47	SS	Eustis	FL	2,665,931.65	324,440.81		260,866.77		Not Available	Not Available
304101388	49	RT	Dover	OH	2,019,201.37	372,223.30		180,139.26		Not Available	Not Available
304140008	8	MU	Orinda	CA	20,733,308.71	1,753,875.86		1,320,659.75		Not Available	Not Available
304140009	9	MU	Sugar Land	TX	19,221,986.18	1,994,326.62		1,579,874.68		Not Available	Not Available
Total	Count = 25				380,071,495.94	46,109,370.36		30,212,276.13




Reports Available at sf.citidirect.com		v. 21.09.28			Page 16 of 36					© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

DELINQUENCY LOAN DETAIL

May 12, 2025


		Actual	Paid	Current P&I	Total P&I	Cumulative	Other Expense	Payment Workout Most Recent
		Principal	Through	Advances	Advances	Accrued Unpaid	Advances	Status		Strategy		Special Serv	Foreclosure	Bankruptcy	REO
Loan ID	OMCR	Balance	Date	(Net of ASER) Outstanding		Interest Advances	Outstanding	(2	)	(3	)	Transfer Date	Date	Date	Date

304101385	1	100,000,000.00	10/06/2021	-	-	-	-	3		1		11/17/2021
300571323	13	12,573,382.07	03/06/2025	74,671.67	149,236.92	3,516.17	-	1		0
304140002	2	72,000,000.00	04/06/2025	234,510.00	234,210.00	1,214.10	-	5		0		11/24/2024
304140034	34	5,155,000.00	04/01/2025	17,784.75	17,763.27	371.42	1,572.50	B		13		09/16/2020
304101400	4	39,159,777.73	04/06/2025	203,674.91	203,511.74	794.51	-	B		13		03/20/2025
304101388	49	2,024,135.73	04/06/2025	12,862.22	12,769.45	-	-	5		8		09/19/2017
Total	Count = 6	230,912,295.53		543,503.55	617,491.38	5,896.20	1,572.50


Reports Available at sf.citidirect.com	v. 21.09.28	Page 17 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

COLLATERAL PERFORMANCE - DELINQUENCY AND LOAN STATUS

May 12, 2025


–




							Delinquent
					(Does not include loans in Bankruptcy, Foreclosure, or REO)

			30	Day			60	Day			90	Day	120			+ Day	Bankruptcy				Foreclosure						REO

Distribution

Date	Count		Balance		Count		Balance		Count		Balance		Count		Balance		Count		Balance		Count		Balance		Count			Balance


	1		12,573,382		0		0		0		0		1		100,000,000		0		0		0		0		0			0
05/12/2025
	4.0	%	3.3	%	0.0	%	0.0	%	0.0	%	0.0	%	4.0	%	26.3	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
04/11/2025
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	3.0	%	21.4	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
03/12/2025
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.9	%	20.8	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
02/12/2025
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.4	%	18.6	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
01/13/2025
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.2	%	16.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
12/12/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.2	%	16.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
11/13/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.2	%	15.9	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
10/11/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.1	%	15.8	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
09/12/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.1	%	15.8	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
08/12/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.1	%	15.7	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
07/12/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.1	%	15.7	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%

	0		0		0		0		0		0		1		100,000,000		0		0		0		0		0			0
06/12/2024
	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	2.1	%	15.7	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%		0.0	%


Reports Available at sf.citidirect.com	v. 21.09.28	Page 18 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

APPRAISAL REDUCTION DETAIL


	May 12, 2025
Most Recent	Cumulative


			Beginning	Ending	Appraisal	Appraisal
Loan ID	OMCR	Property Name	Scheduled Balance	Scheduled Balance	Reduction Amount	Reduction Date	ASER Amount	ASER Amount

304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	94,129,878.79	04/07/2025	-	1,102,148.51


Reports Available at sf.citidirect.com	v. 21.09.28	Page 19 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL APPRAISAL REDUCTION DETAIL

May 12, 2025


Distribution				Beginning	Ending	Appraisal	Appraisal	Most Recent	Cumulative
Date	Loan ID	OMCR	Property Name	Scheduled Balance Scheduled Balance Reduction Amount Reduction Date				ASER Amount	ASER Amount

5/12/2025	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	94,129,878.79	04/07/2025	-	1,102,148.51
4/11/2025	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	94,129,878.79	04/07/2025	-	1,102,148.51
3/12/2025	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	89,858,523.94	03/06/2025	-	1,102,148.51
2/12/2025	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
1/13/2025	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
12/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
11/13/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
10/11/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
9/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
8/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
7/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
6/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
5/10/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
4/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	-	1,102,148.51
3/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	60,012,176.11	03/05/2024	159,048.94	1,102,148.51
2/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	943,099.57
1/12/2024	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	863,000.70
12/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	77,515.03	782,901.83
11/10/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	705,386.80
10/13/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	77,515.03	625,287.93
9/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	547,772.90
8/11/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	467,674.03
7/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	77,515.03	387,575.16
6/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	310,060.13
5/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	77,515.03	229,961.26
4/13/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.53	03/01/2023	80,098.87	152,446.23
3/10/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	28,272,960.38	03/01/2023	72,347.36	72,347.36
2/10/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
1/12/2023	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
12/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
11/14/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
10/13/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
9/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-


Reports Available at sf.citidirect.com	v. 21.09.28	Page 20 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL APPRAISAL REDUCTION DETAIL

May 12, 2025


Distribution				Beginning	Ending	Appraisal	Appraisal	Most Recent	Cumulative
Date	Loan ID	OMCR	Property Name	Scheduled Balance Scheduled Balance Reduction Amount Reduction Date				ASER Amount	ASER Amount

8/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
7/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
6/10/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
5/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
4/12/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
3/11/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
2/11/2022	304101385	1	135 South LaSalle	100,000,000.00	100,000,000.00	-	02/06/2022	-	-
9/14/2020	304101397	17	Magnolia Hotel Omaha	10,410,719.56	10,445,039.27	-	08/06/2020	-	-
8/12/2020	304101397	17	Magnolia Hotel Omaha	10,427,273.39	10,410,719.56	-	08/06/2020	-	-
9/12/2018	304140028	28	Infinity Corporate Center	5,924,901.16	-	-		-	41,157.18
8/10/2018	304140028	28	Infinity Corporate Center	5,933,247.11	5,924,901.16	2,799,940.38	08/06/2018	10,457.97	41,157.18
7/12/2018	304140028	28	Infinity Corporate Center	5,942,281.96	5,933,247.11	2,799,940.38	07/06/2018	10,120.62	30,699.21
6/12/2018	304140028	28	Infinity Corporate Center	5,950,562.60	5,942,281.96	2,799,940.38	06/06/2018	10,457.97	20,578.59
5/11/2018	304140028	28	Infinity Corporate Center	5,959,534.48	5,950,562.60	2,799,940.38	05/07/2018	10,120.62	10,120.62


Reports Available at sf.citidirect.com	v. 21.09.28	Page 21 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

LOAN MODIFICATION DETAIL

May 12, 2025


			Modification	Modification
Loan ID	OMCR	Property Name	Date	Code (4)

304101397	17	Magnolia Hotel Omaha	07/01/2020	8


Reports Available at sf.citidirect.com	v. 21.09.28	Page 22 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL LOAN MODIFICATION DETAIL

May 12, 2025


Distribution				Modification	Modification
Date	Loan ID	OMCR	Property Name	Date	Code (4)

05/12/2025	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
04/11/2025	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
03/12/2025	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
02/12/2025	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
01/13/2025	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
12/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
11/13/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
10/11/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
09/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
08/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
07/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
06/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
05/10/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
04/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
03/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
02/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
01/12/2024	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
12/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
11/10/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
10/13/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
09/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
08/11/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
07/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
06/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
05/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
04/13/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
03/10/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
02/10/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
01/12/2023	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
12/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
11/14/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
10/13/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
09/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8


Reports Available at sf.citidirect.com	v. 21.09.28	Page 23 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL LOAN MODIFICATION DETAIL

May 12, 2025


Distribution				Modification	Modification
Date	Loan ID	OMCR	Property Name	Date	Code (4)

08/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
07/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
06/10/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
05/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
04/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
03/11/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
02/11/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
01/12/2022	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
12/10/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
11/15/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
11/15/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
10/13/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
10/13/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
09/13/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
09/13/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
08/12/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
08/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
07/12/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
07/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
06/11/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
06/11/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
05/12/2021	304140016	16	Crowne Plaza Bloomington	05/06/2020	8
05/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
04/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
03/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
02/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
01/12/2021	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
12/11/2020	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
11/13/2020	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
10/13/2020	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
09/14/2020	304101397	17	Magnolia Hotel Omaha	07/01/2020	8
08/12/2020	304101397	17	Magnolia Hotel Omaha	07/01/2020	8


Reports Available at sf.citidirect.com	v. 21.09.28	Page 24 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

SPECIALLY SERVICED LOAN DETAIL

May 12, 2025


			Special Servicing	Ending	Ending	Most	Most Recent	Most Recent	Most Recent
		Workout	Fee Amount	Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Loan ID	OMCR	Strategy (3)	Plus Adjustments	Balance	Balance	Value	Date	Transfer Date	Return Date

304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	44,500,000.00	11/29/2024	11/17/2021
304101400	4	13	8,158.29	39,090,877.72	39,159,777.73	56,850,000.00	04/16/2015	03/20/2025
304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
Total	Count = 3		32,491.62	144,245,877.72	144,314,777.73	109,250,000.00


Reports Available at sf.citidirect.com	v. 21.09.28	Page 25 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL SPECIALLY SERVICED LOANS

May 12, 2025


				Special Servicing	Ending	Ending	Most	Most Recent	Most Recent	Most Recent
Distribution			Workout	Fee Amount	Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Date	Loan ID	OMCR	Strategy (3)	Plus Adjustments	Balance	Balance	Value	Date	Transfer Date	Return Date

05/12/2025	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	44,500,000.00	11/29/2024	11/17/2021
04/11/2025	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	44,500,000.00	11/29/2024	11/17/2021
03/12/2025	304101385	1	1	19,444.44	100,000,000.00	100,000,000.00	44,500,000.00	11/29/2024	11/17/2021
02/12/2025	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
01/13/2025	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
12/12/2024	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
11/13/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
10/11/2024	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
09/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
08/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
07/12/2024	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
06/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
05/10/2024	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
04/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
03/12/2024	304101385	1	1	20,138.89	100,000,000.00	100,000,000.00	67,700,000.00	01/08/2024	11/17/2021
02/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
01/12/2024	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
12/12/2023	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
11/10/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
10/13/2023	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
09/12/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
08/11/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
07/12/2023	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
06/12/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
05/12/2023	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
04/13/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
03/10/2023	304101385	1	1	19,444.44	100,000,000.00	100,000,000.00	90,000,000.00	01/01/2023	11/17/2021
02/10/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
01/12/2023	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
12/12/2022	304101385	1	1	20,833.33	100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
11/14/2022	304101385	1	1	21,527.78	100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
10/13/2022	304101385	1	10	20,833.33	100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021


Reports Available at sf.citidirect.com	v. 21.09.28	Page 26 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL SPECIALLY SERVICED LOANS

May 12, 2025


				Special Servicing		Ending	Ending	Most	Most Recent	Most Recent	Most Recent
Distribution			Workout	Fee Amount		Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Date	Loan ID	OMCR	Strategy (3)	Plus Adjustments		Balance	Balance	Value	Date	Transfer Date	Return Date

09/12/2022	304101385	1	10	21,527.78		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
08/12/2022	304101385	1	10	21,527.78		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
07/12/2022	304101385	1	10	20,833.33		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
06/10/2022	304101385	1	10	21,527.78		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
05/12/2022	304101385	1	10	20,833.33		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
04/12/2022	304101385	1	10	21,527.78		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
03/11/2022	304101385	1	10	19,444.44		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
02/11/2022	304101385	1	13	21,527.78		100,000,000.00	100,000,000.00	130,000,000.00	01/01/2022	11/17/2021
01/12/2022	304101385	1	13	21,527.78		100,000,000.00	100,000,000.00	330,000,000.00	03/30/2015	11/17/2021
12/10/2021	304101385	1	13	8,333.33		100,000,000.00	100,000,000.00	330,000,000.00	03/30/2015	11/17/2021
05/11/2018	304101388	49	8	(22,983.33	)	2,364,016.73	2,364,016.73	3,825,000.00	04/01/2015		04/25/2018
04/12/2018	304101388	49	9	3,500.00		2,367,605.83	2,367,605.83	3,825,000.00	04/01/2015	09/19/2017
03/12/2018	304101388	49	13	3,500.00		2,370,872.60	2,378,289.43	3,825,000.00	04/01/2015	09/19/2017
02/12/2018	304101388	49	13	3,500.00		2,375,052.68	2,378,289.43	3,825,000.00	04/01/2015	09/19/2017
01/12/2018	304101388	49	13	3,500.00		2,378,289.43	2,378,289.43	3,825,000.00	04/01/2015	09/19/2017
12/12/2017	304101388	49	13	3,500.00		2,381,513.14	2,385,033.98	3,825,000.00	04/01/2015	09/19/2017
11/10/2017	304101388	49	13	3,500.00		2,385,033.98	2,391,725.13	3,825,000.00	04/01/2015	09/19/2017
10/13/2017	304101388	49	13	1,983.33		2,388,230.50	2,391,725.13	3,825,000.00	04/01/2015	09/19/2017
10/13/2020	304101397	17	8	-		10,445,039.27	10,445,039.27	13,000,000.00	04/20/2020	04/06/2020	09/02/2020
09/14/2020	304101397	17	1	3,500.00		10,445,039.27	10,445,039.27	13,000,000.00	04/20/2020	04/06/2020
08/12/2020	304101397	17	1	3,500.00		10,410,719.56	10,445,039.27	13,000,000.00	04/20/2020	04/06/2020
07/10/2020	304101397	17	98	3,500.00		10,427,273.39	10,445,039.27	16,600,000.00	04/01/2015	04/06/2020
06/12/2020	304101397	17	98	3,500.00		10,445,039.27	10,445,039.27	16,600,000.00	04/01/2015	04/06/2020
05/12/2020	304101397	17	13	3,500.00		10,461,463.26	10,461,463.26	16,600,000.00	04/01/2015	04/06/2020
04/10/2020	304101397	17	13	-		10,479,103.95	10,495,399.07	16,600,000.00	04/01/2015	04/06/2020
05/12/2025	304101400	4	13	8,158.29		39,090,877.72	39,159,777.73	56,850,000.00	04/16/2015	03/20/2025
04/11/2025	304101400	4	13	4,630.61		39,159,777.73	39,223,957.00	56,850,000.00	04/16/2015	03/20/2025
03/12/2025	304140002	2	1	14,000.00		72,000,000.00	72,000,000.00	544,500,000.00	03/02/2015	11/24/2024
02/12/2025	304140002	2	1	15,500.00		72,000,000.00	72,000,000.00	544,500,000.00	03/02/2015	11/24/2024
01/13/2025	304140002	2	1	15,500.00		72,000,000.00	72,000,000.00	544,500,000.00	03/02/2015	11/24/2024
12/12/2024	304140002	2	98	5,500.00		72,000,000.00	72,000,000.00	544,500,000.00	03/02/2015
11/15/2021	304140016	16	6	(25,040.30	)	-	-	31,900,000.00	12/01/2014	02/04/2021


Reports Available at sf.citidirect.com	v. 21.09.28	Page 27 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL SPECIALLY SERVICED LOANS

May 12, 2025


				Special Servicing	Ending	Ending	Most	Most Recent	Most Recent	Most Recent
Distribution			Workout	Fee Amount	Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Date	Loan ID	OMCR	Strategy (3)	Plus Adjustments	Balance	Balance	Value	Date	Transfer Date	Return Date

10/13/2021	304140016	16	6	2,262.80	10,840,353.25	10,840,353.25	31,900,000.00	12/01/2014	02/04/2021
09/13/2021	304140016	16	6	2,342.44	10,861,430.72	10,881,026.79	31,900,000.00	12/01/2014	02/04/2021
08/12/2021	304140016	16	6	2,346.65	10,881,026.79	10,921,389.82	31,900,000.00	12/01/2014	02/04/2021
07/12/2021	304140016	16	2	2,275.29	10,900,544.70	10,921,389.82	31,900,000.00	12/01/2014	02/04/2021
06/11/2021	304140016	16	2	2,355.30	10,921,389.82	10,940,746.76	31,900,000.00	12/01/2014	02/04/2021
05/12/2021	304140016	16	2	2,283.63	10,940,746.76	11,004,001.62	31,900,000.00	12/01/2014	02/04/2021
04/12/2021	304140016	16	2	2,363.89	10,961,436.70	11,004,001.62	31,900,000.00	12/01/2014	02/04/2021
03/12/2021	304140016	16	6	2,139.67	10,980,633.92	11,004,001.62	31,900,000.00	12/01/2014	02/04/2021
02/12/2021	304140016	16	6	2,373.01	11,004,001.62	11,041,980.66	31,900,000.00	12/01/2014	02/04/2021
01/12/2021	304140016	16	6	2,377.09	11,023,029.08	11,041,980.66	31,900,000.00	12/01/2014	11/06/2020
12/11/2020	304140016	16	98	1,920.53	11,041,980.66	11,062,279.84	31,900,000.00	12/01/2014	11/06/2020
09/12/2018	304140028	28	8	-	-	-	3,875,000.00	10/12/2017	09/19/2017
08/10/2018	304140028	28	2	3,500.00	5,924,901.16	5,986,255.08	3,875,000.00	10/12/2017	09/19/2017
07/12/2018	304140028	28	2	3,500.00	5,933,247.11	5,986,255.08	3,875,000.00	10/12/2017	09/19/2017
06/12/2018	304140028	28	2	3,500.00	5,942,281.96	5,986,255.08	3,875,000.00	10/12/2017	09/19/2017
05/11/2018	304140028	28	2	3,500.00	5,950,562.60	5,986,255.08	8,500,000.00	03/12/2015	09/19/2017
04/12/2018	304140028	28	2	3,500.00	5,959,534.48	5,986,255.08	8,500,000.00	03/12/2015	09/19/2017
03/12/2018	304140028	28	2	3,500.00	5,967,750.30	5,986,255.08	8,500,000.00	03/12/2015	09/19/2017
02/12/2018	304140028	28	2	3,500.00	5,978,109.06	5,994,370.49	8,500,000.00	03/12/2015	09/19/2017
01/12/2018	304140028	28	2	3,500.00	5,986,255.08	5,994,370.49	8,500,000.00	03/12/2015	09/19/2017
12/12/2017	304140028	28	2	3,500.00	5,994,370.49	6,003,183.05	8,500,000.00	03/12/2015	09/19/2017
11/10/2017	304140028	28	2	3,500.00	6,003,183.05	6,011,234.86	8,500,000.00	03/12/2015	09/19/2017
10/13/2017	304140028	28	13	1,983.33	6,011,234.86	6,019,986.09	8,500,000.00	03/12/2015	09/19/2017
05/12/2025	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
04/11/2025	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
03/12/2025	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
02/12/2025	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
01/13/2025	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
12/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
11/13/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
10/11/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
09/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020


Reports Available at sf.citidirect.com	v. 21.09.28	Page 28 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL SPECIALLY SERVICED LOANS

May 12, 2025


				Special Servicing	Ending	Ending	Most	Most Recent	Most Recent	Most Recent
Distribution			Workout	Fee Amount	Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Date	Loan ID	OMCR	Strategy (3)	Plus Adjustments	Balance	Balance	Value	Date	Transfer Date	Return Date

08/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
07/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
06/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
05/10/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
04/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
03/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
02/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
01/12/2024	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
12/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
11/10/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
10/13/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
09/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
08/11/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
07/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
06/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
05/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
04/13/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
03/10/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
02/10/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
01/12/2023	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
12/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
11/14/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
10/13/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
09/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
08/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
07/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
06/10/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
05/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
04/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
03/11/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
02/11/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
01/12/2022	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020


Reports Available at sf.citidirect.com	v. 21.09.28	Page 29 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL SPECIALLY SERVICED LOANS

May 12, 2025


				Special Servicing	Ending	Ending	Most	Most Recent	Most Recent	Most Recent
Distribution			Workout	Fee Amount	Scheduled	Actual	Recent	Valuation	Special Servicer	Master Servicer
Date	Loan ID	OMCR	Strategy (3)	Plus Adjustments	Balance	Balance	Value	Date	Transfer Date	Return Date

12/10/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
11/15/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
10/13/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
09/13/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
08/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
07/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
06/11/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
05/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
04/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
03/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
02/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
01/12/2021	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
12/11/2020	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
11/13/2020	304140034	34	13	3,500.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020
10/13/2020	304140034	34	13	1,750.00	5,155,000.00	5,155,000.00	7,900,000.00	03/08/2015	09/16/2020


Reports Available at sf.citidirect.com	v. 21.09.28	Page 30 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

UNSCHEDULED PRINCIPAL DETAIL

May 12, 2025


		Liquidation /	Liquid / Prepay	Principal	Principal	Prepayment Interest	Prepayment	Yield Maintenance
Loan ID	OMCR	Prepayment Date	Code (5)	Collections	Adjustments	Excess / (Shortfall)	Penalties (PPP)	Penalties (YM)

304140014	14	05/06/2025	5	11,280,703.66	-	-	-	-
304101380	15	05/06/2025	5	9,913,266.50	-	-	-	-
304140027	27	05/06/2025	5	5,351,921.86	-	-	-	-
304140038	38	05/06/2025	5	3,992,703.35	-	-	-	-
304140039	39	04/18/2025	5	3,650,567.09	-	-	-	-
304101386	42	05/05/2025	5	3,035,428.69	-	-	-	-
304140005	5	04/30/2025	5	24,508,011.66	-	-	-	-
304101392	6	05/06/2025	2	25,778,504.22	-	-	-	-
Total	Count = 8			87,511,107.03	-	-	-	-


Reports Available at sf.citidirect.com	v. 21.09.28	Page 31 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31

Commercial Mortgage Pass-Through Certificates, Series 2015-GC31

HISTORICAL UNSCHEDULED PRINCIPAL DETAIL


	May 12, 2025




Prepayment	Yield Maintenance
(PPP)	Penalties (YM)


Distribution			Liquidation /	Liquid / Prepay	Principal		Principal	Prepayment Interest
Date	Loan ID	OMCR	Prepayment Date	Code (5)	Collections		Adjustments	Excess / (Shortfall)	Penalties

5/12/2025	304140014	14	05/06/2025	5	11,280,703.66		-	-	-	-
5/12/2025	304101380	15	05/06/2025	5	9,913,266.50		-	-	-	-
5/12/2025	304140027	27	05/06/2025	5	5,351,921.86		-	-	-	-
5/12/2025	304140038	38	05/06/2025	5	3,992,703.35		-	-	-	-
5/12/2025	304140039	39	04/18/2025	5	3,650,567.09		-	-	-	-
5/12/2025	304101386	42	05/05/2025	5	3,035,428.69		-	-	-	-
5/12/2025	304140005	5	04/30/2025	5	24,508,011.66		-	-	-	-
5/12/2025	304101392	6	05/06/2025	2	25,778,504.22		-	-	-	-
4/11/2025	304140021	21	03/25/2025	2	7,428,747.86		-	-	-	-
4/11/2025	300571333	26	04/04/2025	2	5,600,318.71		-	-	-	-
3/12/2025	304140018	18	03/06/2025	5	9,788,299.63		-	-	-	-
3/12/2025	304140029	29	02/28/2025	2	5,126,957.32		-	-	-	-
3/12/2025	300571331	32	03/06/2025	5	4,770,206.49		-	-	-	-
3/12/2025	300571328	37	03/06/2025	5	4,001,512.55		-	-	-	-
3/12/2025	304140044	44	03/06/2025	2	3,085,086.00		-	-	-	-
3/12/2025	300571324	50	03/06/2025	5	2,033,561.79		-	-	-	-
3/12/2025	300571327	7	03/06/2025	2	25,257,522.37		-	-	-	-
2/12/2025	300571310	11	02/06/2025	5	16,740,126.67		-	-	-	-
2/12/2025	301461017	19	02/06/2025	2	8,761,441.70		-	-	-	-
2/12/2025	304140003	3	02/06/2025	2	57,864,351.61		-	-	-	-
2/12/2025	304140033	33	02/06/2025	5	4,304,882.57		-	-	-	-
11/13/2024	304140030	30	11/06/2024	5	5,430,806.62		-	-	-	-
5/12/2022	304101397	17	08/06/2021	1	218,224.17		-	-	-	-
11/15/2021	304140016	16	10/15/2021	9	10,820,594.32		-	-	-	1,973,242.03
9/13/2021	304101372	48	08/27/2021	9	2,333,597.23		-	-	-	72,353.89
9/14/2020	304101397	17		0	(34,319.71	)	-	-	-	-
9/12/2018	304140028	28	08/28/2018	3	4,822,832.84		1,093,690.89	-	-	-


Reports Available at sf.citidirect.com	v. 21.09.28	Page 32 of 36	© Copyright 2025 Citigroup


Citigroup Commercial Mortgage Trust 2015-GC31
Commercial Mortgage Pass-Through Certificates, Series 2015-GC31										May 12, 2025
LIQUIDATED LOAN DETAIL


		Beginning	Most	Liquidation	Net		Net	Realized	Date of		Loss with
		Scheduled	Recent	Sales	Proceeds	Liquidation	Proceeds	Loss to	Current	Current Cumulative	Cumulative
Loan ID	OMCR	Balance	Value	Price	Received	Expense	Available	Trust	Adj. to Loan	Adj. to Loan Adj. to Loan	Adj. to Trust
No Loans liquidated to Report.




Reports Available at sf.citidirect.com		v. 21.09.28				Page 33 of 36				© Copyright 2025 Citigroup


Citigroup Commercial Mortgage Trust 2015-GC31
Commercial Mortgage Pass-Through Certificates, Series 2015-GC31													May 12, 2025

HISTORICAL LIQUIDATED LOAN


			Beginning	Most	Liquidation	Net		Net	Realized		Date of			Loss with
Distribution			Scheduled	Recent	Sales	Proceeds	Liquidation	Proceeds	Loss to		Current	Current	Cumulative	Cumulative
Date	Loan ID	OMCR	Balance	Value	Price	Received	Expense	Available	Trust		Adj. to Loan	Adj. to Loan Adj. to Loan Adj. to Trust

04/13/2023	304140016	16	-	-	-	-	-	-	-			600.00	-	-
08/12/2022	304140028	28	-	-	-	-	-	-	(57,026.11	)		-	-	(57,026.11	)
11/15/2021	304140016	16	10,840,353.25	31,900,000.00	-	13,078,247.35	2,237,894.10	10,840,353.25	-			-	-	-
09/12/2018	304140028	28	5,924,901.16	3,875,000.00	-	5,400,800.31	569,590.04	4,831,210.27	1,093,690.89			-	-	1,093,690.89




Reports Available at sf.citidirect.com			v. 21.09.28				Page 34 of 36						© Copyright 2025 Citigroup


Citigroup Commercial Mortgage Trust 2015-GC31
Commercial Mortgage Pass-Through Certificates, Series 2015-GC31					May 12, 2025

CREFC® INVESTOR REPORTING PACKAGE LEGENDS

1\|CREFC Investor Reporting Package Legends
	Property Type (1)		Workout Strategy (3)		Liquidation/Prepayment Code (5)

MF	Multifamily	1	Modification	1	Partial Liquidation (Curtailment)
RT	Retail	2	Foreclosure	2	Payoff Prior To Maturity
HC	HealthCare	3	Bankruptcy	3	Disposition / Liquidation
IN	Industrial	4	Extension	4	Repurchase / Substitution
MH	Mobile Home Park	5	Note Sale	5	Full Payoff At Maturity
OF	Office	6	DPO	6	DPO
MU	Mixed Use	7	REO	7	Liquidation prior to 7/1/2006
LO	Lodging	8	Resolved	8	Payoff With Penalty
SS	Self Storage	9	Pending Return to Master Servicer	9	Payoff With Yield Maintenance
SE	Securities	10	Deed In Lieu of Foreclosure	10	Curtailment With Penalty
CH	Cooperative Housing	11	Full Payoff	11	Curtailment With Yield Maintenance
ZZ	Missing Information	12	Reps and Warranties
SF	SF	13	TBD
WH	Warehouse	98	Other
OT	Other

Modification Code (4)

	Payment Status of Loan (2)
		1	Maturity Date Extension
A	In Grace Period	2	Amortization Change
B	Late, but less than 30 Days	3	Principal Write-Off
0	Current	4	Blank (formerly Combination)
1	30-59 Days Delinquent	5	Temporary Rate Reduction
2	60-89 Days Delinquent	6	Capitalization of Interest
3	90-120 Days Delinquent	7	Capitalization of Taxes
4	Performing Matured Balloon	8	Other
5	Non Performing Matured Balloon	9	Combination
6	121+ Days Delinquent	10	Forbearance




Reports Available at sf.citidirect.com		v. 21.09.28	Page 35 of 36		© Copyright 2025 Citigroup


Citigroup Commercial Mortgage Trust 2015-GC31
Commercial Mortgage Pass-Through Certificates, Series 2015-GC31			May 12, 2025
NOTES
No Notes available for this deal at this time.




Reports Available at sf.citidirect.com	v. 21.09.28	Page 36 of 36	© Copyright 2025 Citigroup

Citigroup Commercial Mortgage Trust 2015-GC31 10-D