Exhibit 99.1

MONTHLY SERVICER'S CERTIFICATE

CARMAX BUSINESS SERVICES, LLC

CARMAX AUTO OWNER TRUST

SERIES 2020-4

Collection Period

09/01/24-09/30/24

Determination Date

10/9/2024

Distribution Date

10/15/2024

Additional information, including defined terms, can be found in the prospectus on the SEC's EDGAR system (http://www.sec.gov) under File No. 333-228375-08.


Pool Balance
1.	Pool Balance on the close of the last day of the preceding Collection Period			$	180,903,542.84
2.	Collections allocable to Principal			$	12,613,615.59
3.	Purchase Amount allocable to Principal			$	0.00
4.	Defaulted Receivables			$	317,019.47
5.	Pool Balance on the close of the last day of the related Collection Period			$	167,972,907.78
	(Ln1 - Ln2 - Ln3 - Ln4)
6.	Total number of Receivables outstanding on the close of the last day of the related Collection Period			30,892
7.	Initial Pool Balance			$	1,506,024,109.27
		Beginning of Period		End of Period
8.	Note Balances
	a. Class A-1 Note Balance	$	0.00	$	0.00
	b. Class A-2 Note Balance	$	0.00	$	0.00
	c. Class A-3 Note Balance	$	0.00	$	0.00
	d. Class A-4 Note Balance	$	64,189,446.40	$	51,258,811.34
	e. Class B Note Balance	$	48,190,000.00	$	48,190,000.00
	f. Class C Note Balance	$	38,400,000.00	$	38,400,000.00
	g. Class D Note Balance	$	24,100,000.00	$	24,100,000.00
	h. Note Balance (sum a - g)	$	174,879,446.40	$	161,948,811.34
9.	Pool Factors
	a. Class A-1 Note Pool Factor	0.0000000		0.0000000
	b. Class A-2 Note Pool Factor	0.0000000		0.0000000
	c. Class A-3 Note Pool Factor	0.0000000		0.0000000
	d. Class A-4 Note Pool Factor	0.5122452		0.4090560
	e. Class B Note Pool Factor	1.0000000		1.0000000
	f. Class C Note Pool Factor	1.0000000		1.0000000
	g. Class D Note Pool Factor	1.0000000		1.0000000
	h. Note Pool Factor	0.1165863		0.1079659
10.	Overcollateralization Target Amount			$	6,024,096.44
11.	Current overcollateralization amount (Pool Balance - Note Balance)			$	6,024,096.44
12.	Weighted Average Coupon			8.44		%
13.	Weighted Average Original Term	months		68.22
14.	Weighted Average Remaining Term	months		18.69
Collections
15.	Finance Charges:
	a. Collections allocable to Finance Charge			$	1,299,720.25
	b. Liquidation Proceeds allocable to Finance Charge			$	1,511.72
	c. Purchase Amount allocable to Finance Charge			$	0.00
	d. Available Finance Charge Collections (sum a - c)			$	1,301,231.97
16.	Principal:
	a. Collections allocable to Principal			$	12,613,615.59
	b. Liquidation Proceeds allocable to Principal			$	144,815.71
	c. Purchase Amount allocable to Principal			$	0.00
	d. Available Principal Collections (sum a - c)			$	12,758,431.30


17.	Total Finance Charge and Principal Collections (15d + 16d)	$	14,059,663.27
18.	Interest Income from Collection Account	$	51,211.28
19.	Simple Interest Advances	$	0.00
20.	Available Collections (Ln17 + 18 + 19)	$	14,110,874.55
Available Funds
21.	Available Collections	$	14,110,874.55
22.	Reserve Account Draw Amount	$	0.00
23.	Available Funds	$	14,110,874.55
Application of Available Funds
24.	Servicing Fee	0.15		%
	a. Monthly Servicing Fee	$	150,752.95
	b. Amount Unpaid from Prior Months	$	0.00
	c. Amount Paid	$	150,752.95
	d. Shortfall Amount (a + b - c)	$	0.00
25.	Unreimbursed Servicer Advances	$	0.00
26.	Successor Servicer and Asset Representations Reviewer Unpaid Expenses and Indemnity Amounts
	a. Successor Servicer Unpaid Transition Expenses and Indemnity Amounts (Capped at $175,000 annually)	$	0.00
	b. Successor Servicer Amount Paid	$	0.00
	c. Successor Servicer Shortfall Amount (a - b)	$	0.00
	d. Asset Representations Reviewer Fees, Expenses and Indemnity Amounts (Capped at $175,000 annually)	$	0.00
	e. Asset Representations Reviewer Amount Paid	$	0.00
	f. Asset Representations Reviewer Shortfall Amount (d - e)	$	0.00
27.	Class A Noteholder Interest Amounts
	a. Class A-1 Monthly Interest	$	0.00
	b. Additional Note Interest related to Class A-1 Monthly Interest	$	0.00
	c. Interest Due on Additional Note Interest related to Class A-1 Monthly Interest	$	0.00
	d. Total Class A-1 Note Interest (sum a - c)	$	0.00
	e. Class A-2 Monthly Interest	$	0.00
	f. Additional Note Interest related to Class A-2 Monthly Interest	$	0.00
	g. Interest Due on Additional Note Interest related to Class A-2 Monthly Interest	$	0.00
	h. Total Class A-2 Note Interest (sum e - g)	$	0.00
	i. Class A-3 Monthly Interest	$	0.00
	j. Additional Note Interest related to Class A-3 Monthly Interest	$	0.00
	k. Interest Due on Additional Note Interest related to Class A-3 Monthly Interest	$	0.00
	l. Total Class A-3 Note Interest (sum i - k)	$	0.00
	m. Class A-4 Monthly Interest	$	33,699.46
	n. Additional Note Interest related to Class A-4 Monthly Interest	$	0.00
	o. Interest Due on Additional Note Interest related to Class A-4 Monthly Interest	$	0.00
	p. Total Class A-4 Note Interest (sum m - o)	$	33,699.46
28.	Priority Principal Distributable Amount	$	0.00
29.	Class B Noteholder Interest Amount
	a. Class B Monthly Interest	$	34,134.58
	b. Additional Note Interest related to Class B Monthly Interest	$	0.00
	c. Interest Due on Additional Note Interest related to Class B Monthly Interest	$	0.00
	d. Total Class B Note Interest (sum a - c)	$	34,134.58
30.	Secondary Principal Distributable Amount	$	0.00
31.	Class C Noteholder Interest Amount
	a. Class C Monthly Interest	$	41,600.00
	b. Additional Note Interest related to Class C Monthly Interest	$	0.00
	c. Interest Due on Additional Note Interest related to Class C Monthly Interest	$	0.00
	d. Total Class C Note Interest (sum a - c)	$	41,600.00
32.	Tertiary Principal Distributable Amount	$	0.00


33.	Class D Noteholder Interest Amount
	a. Class D Monthly Interest	$	35,145.83
	b. Additional Note Interest related to Class D Monthly Interest	$	0.00
	c. Interest Due on Additional Note Interest related to Class D Monthly Interest	$	0.00


	d. Total Class D Note Interest (sum a - c)	$	35,145.83
34.	Quaternary Principal Distributable Amount	$	6,906,538.62
35.	Required Payment Amount (Ln 24 + Ln 26 + (sum of Ln 27 through Ln 34))	$	7,201,871.44
36.	Reserve Account Deficiency	$	0.00
37.	Regular Principal Distributable Amount	$	6,024,096.44
38.	Remaining Unpaid Servicer Transition Expenses and Additional Servicing Fees, if any	$	0.00
39.	Remaining Unpaid Trustee and Asset Representations Reviewer Fees, Expenses and Indemnity Amounts, if any
	a. Remaining Unpaid Trustee Fees, Expenses and Indemnity Amounts	$	0.00
	b. Remaining Unpaid Asset Representations Reviewer Fees, Expenses and Indemnity Amounts	$	0.00
40.	Remaining Unpaid Successor Servicer Indemnity Amounts, if any	$	0.00
Collection Account Activity		0.15		%
41.	Deposits
	a. Total Daily Deposits of Finance Charge Collections	$	1,301,231.97
	b. Total Daily Deposits of Principal Collections	$	12,758,431.30
	c. Withdrawal from Reserve Account	$	0.00
	d. Interest Income	$	51,211.28
	e. Total Deposits to Collection Account (sum a - d)	$	14,110,874.55
42.	Withdrawals
	a. Servicing Fee and Unreimbursed Servicer Advances	$	150,752.95
	b. Successor Servicer Transition Expenses and Indemnity Amounts	$	0.00
	c. Deposit to Note Payment Account for Monthly Note Interest/Principal	$	13,075,214.93
	d. Deposit to Reserve Account	$	0.00
	e. Excess Collections (Deposit to Certificate Payment Account for payment to Certificateholder)	$	884,906.67
	f. Total Withdrawals from Collection Account (sum a - e)	$	14,110,874.55
Note Payment Account Activity
43.	Deposits
	a. Class A-1 Interest Distribution	$	0.00
	b. Class A-2 Interest Distribution	$	0.00
	c. Class A-3 Interest Distribution	$	0.00
	d. Class A-4 Interest Distribution	$	33,699.46
	e. Class B Interest Distribution	$	34,134.58
	f. Class C Interest Distribution	$	41,600.00
	g. Class D Interest Distribution	$	35,145.83
	h. Class A-1 Principal Distribution	$	0.00
	i. Class A-2 Principal Distribution	$	0.00
	j. Class A-3 Principal Distribution	$	0.00
	k. Class A-4 Principal Distribution	$	12,930,635.06
	l. Class B Principal Distribution	$	0.00
	m. Class C Principal Distribution	$	0.00
	n. Class D Principal Distribution	$	0.00
	o. Total Deposits to Note Payment Account (sum a - n)	$	13,075,214.93
44.	Withdrawals
	a. Class A-1 Distribution	$	0.00
	b. Class A-2 Distribution	$	0.00
	c. Class A-3 Distribution	$	0.00
	d. Class A-4 Distribution	$	12,964,334.52
	e. Class B Distribution	$	34,134.58
	f. Class C Distribution	$	41,600.00
	g. Class D Distribution	$	35,145.83
	h. Total Withdrawals from Note Payment Account (sum a - g)	$	13,075,214.93


Certificate Payment Account Activity
45.	Deposits to Certificate Payment Account from Excess Collections	$	884,906.67
46.	Withdrawals from Certificate Payment Account for Certificateholder Distribution	$	884,906.67
Required Reserve Account Amount		0.15		%
47.	Required Reserve Account Amount (0.25% of Initial Pool Balance)	$	7,530,120.55
Reserve Account Reconciliation
48.	Beginning Balance (as of end of preceding Distribution Date)	$	7,530,120.55
49.	Investment Earnings	$	31,222.80
50.	Reserve Account Draw Amount	$	0.00
51.	Reserve Account Amount (Ln 48 + Ln 49 - Ln 50)	$	7,561,343.35
52.	Deposit from Available Funds (Ln 42d)	$	0.00
53.	If Reserve Account Balance exceeds Required Reserve Account Amount, payment to
	a. the Note Payment Account for the payment of principal to the extent of any unfunded Regular Principal Distribution Amount; and	$	0.00
	b. any Successor Servicer for the payment of any unfunded Transition Costs and Additional Servicing Fee	$	0.00
54.	Payment to Depositor if Reserve Account Balance exceeds Required Reserve Account Amount and to the extent no unfunded amounts described in Ln 53 exist	$	31,222.80
55.	Ending Balance (Ln51 + Ln52 - Ln53 - Ln54)	$	7,530,120.55
56.	Reserve Account Deficiency (Ln48 - Ln55)	$	0.00
Instructions to the Trustee
57.	Amount to be deposited from the Reserve Account into the Collection Account	$	0.00
58.	Amount to be paid to Servicer from the Collection Account	$	150,752.95
59.	Amount to be deposited from the Collection Account into the Note Payment Account	$	13,075,214.93
60.	Amount to be deposited from the Collection Account into the Certificate Payment Account	$	884,906.67
61.	Amount to be deposited from the Collection Account into the Reserve Account	$	0.00
62.	Amount to be deposited from the Reserve Account, if Reserve Account Balance exceeds Required Reserve Account Amount, into
	a. the Note Payment Account for any unfunded Regular Principal Distributable Amount	$	0.00
	b. the Depositor, if no unfunded Regular Principal distributable amount exists	$	31,222.80
63.	Amount to be paid to Class A-1 Noteholders from the Note Payment Account	$	0.00
64.	Amount to be paid to Class A-2 Noteholders from the Note Payment Account	$	0.00
65.	Amount to be paid to Class A-3 Noteholders from the Note Payment Account	$	0.00
66.	Amount to be paid to Class A-4 Noteholders from the Note Payment Account	$	12,964,334.52
67.	Amount to be paid to Class B Noteholders from the Note Payment Account	$	34,134.58
68.	Amount to be paid to Class C Noteholders from the Note Payment Account	$	41,600.00
69.	Amount to be paid to Class D Noteholders from the Note Payment Account	$	35,145.83
70.	Amount to be paid to Certificateholders from the Certificate Payment Account with respect to Excess Collections	$	884,906.67


Delinquency Activity
		Number of Loans	Principal Balance
71.	Delinquency Analysis
	a. 31 to 60 days past due	731	$	5,977,850.40
	b. 61 to 90 days past due	355	$	3,164,446.41
	c. 91 to 120 days past due	76	$	595,090.54
	d. 121 or more days past due	1	$	5,776.16
	e. Total Past Due (sum a - d)	1,163	$	9,743,163.51
	f. Delinquent Loans as a percentage of end of period Pool Balance (Ln 71e / Ln 5)		5.8004		%

72.	Has a Delinquency Trigger Event occurred?		No

Loss Activity
		Number of Loans	Principal Balance

73.	Defaulted Receivables (charge-offs)	41	$	317,019.47
74.	Recoveries	106	$	146,327.43
75.	Net Losses (Ln 73 - Ln 74)		$	170,692.04
76.	Ratio of Net Losses to Beginning of Period Pool Balance (Ln 75 / Ln 1)		0.0944		%

Cumulative Loss Activity
		Number of Loans	Principal Balance

77.	Defaulted Receivables (charge-offs)	2,534	$	33,388,196.81
78.	Recoveries	2,109	$	17,317,965.67
79.	Cumulative Net Losses (Ln 77 - Ln 78)		$	16,070,231.14
80.	Ratio of Cumulative Net Losses to Initial Pool Balance (Ln 79 / Ln 7)		1.0671		%
81.	Average Net Loss on Defaulted Receivables		$	6,341.84

Other Servicing Information

82.	Principal Balance of Receivables extended during the Collection Period		$	2,884,394.41
83.	Pool Balance on the close of the last day of the preceding Collection Period		$	180,903,542.84
84.	Ratio of extensions to pool balance (Ln 82 / Ln 83)		1.59		%

IN WITNESS WHEREOF, the undersigned has duly executed this certificate on October 9, 2024.


CARMAX BUSINESS SERVICES, LLC

As Servicer

By:			/s/ Greg Dostich

Name:			Greg Dostich

Title:			Vice President and Treasurer

CarMax Auto Owner Trust 2020-4 10-D