Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Summary Collateral Information
	Description
Group 1
Pool 8081	HYBRID ARM
Pool 8082	HYBRID ARM
Group 2
Pool 8083	HYBRID ARM
Group 3
Pool 8084	HYBRID ARM
Pool 8085	HYBRID ARM

General Information
Description	Total	Pool 8081	Pool 8082	Pool 8083	Pool 8084	Pool 8085
Weighted Average Pass Through Rate	5.68313%	5.57297%	5.74541%	5.86485%	5.51747%	5.71168%
Weighted Average Mortgage Interest Rate	6.30361%	6.32297%	6.37041%	6.23985%	6.20374%	6.29011%
Weighted Average Remaining Term (in Months)	354.35270	357.83289	357.70603	357.80057	334.67149	335.83053
Weighted Average Loan Age (in Months)	5.46778	2.16711	2.29397	2.19943	23.19652	23.83157
Average Ending Scheduled Principal Balance	$691,689.06	$775,893.64	$825,429.23	$817,741.12	$407,378.72	$387,073.99
Remaining Loan Count	2388	858	437	456	289	348
Ending Scheduled Principal Balance	$1,651,753,468.95	$665,716,743.88	$360,712,575.38	$372,889,951.07	$117,732,450.89	$134,701,747.73

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

General Information (Continued)
Description	Group 1	Group 3
Weighted Average Pass Through Rate	5.63330%	5.62206%
Weighted Average Mortgage Interest Rate	6.33956%	6.25025%
Weighted Average Remaining Term (in Months)	357.78831	335.28997
Weighted Average Loan Age (in Months)	2.21169	23.53539
Average Ending Scheduled Principal Balance	$792,609.51	$396,286.03
Remaining Loan Count	1295	637
Ending Scheduled Principal Balance	$1,026,429,319.26	$252,434,198.62

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Geographic Distribution
Total			Pool 8081			Pool 8082
State	Percent	Ending Scheduled Principal Balance	State	Percent	Ending Scheduled Principal Balance	State	Percent	Ending Scheduled Principal Balance
CA	$1,131,236,240.07	68.49%	CA	$490,148,256.77	73.63%	CA	$227,876,054.30	63.17%
NY	$88,125,605.81	5.34%	FL	$32,428,338.58	4.87%	NY	$20,605,949.45	5.71%
WA	$57,594,750.09	3.49%	NY	$23,141,620.94	3.48%	WA	$16,849,870.67	4.67%
FL	$56,216,321.94	3.40%	WA	$20,689,310.96	3.11%	IL	$16,304,281.32	4.52%
IL	$46,739,772.54	2.83%	IL	$20,049,400.59	3.01%	FL	$12,547,196.17	3.48%
OTHER	$271,840,778.50	16.46%	OTHER	$79,259,816.04	11.91%	OTHER	$66,529,223.47	18.44%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Geographic Distribution
Pool 8083			Pool 8084			Pool 8085
State	Percent	Ending Scheduled Principal Balance	State	Percent	Ending Scheduled Principal Balance	State	Percent	Ending Scheduled Principal Balance
CA	$278,992,107.72	74.82%	CA	$49,111,453.28	41.71%	CA	$85,108,368.00	63.18%
NY	$22,945,624.82	6.15%	NY	$13,760,676.24	11.69%	NY	$7,671,734.36	5.70%
WA	$11,686,154.75	3.13%	CT	$6,785,893.43	5.76%	WA	$4,397,605.29	3.26%
CT	$10,651,589.04	2.86%	MA	$5,945,773.03	5.05%	FL	$4,354,740.89	3.23%
CO	$5,771,343.75	1.55%	NJ	$5,405,772.44	4.59%	CO	$4,162,757.53	3.09%
OTHER	$42,843,130.99	11.49%	OTHER	$36,722,882.47	31.19%	OTHER	$29,006,541.66	21.53%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Geographic Distribution
Group 1			Group 3
State	Percent	Ending Scheduled Principal Balance	State	Percent	Ending Scheduled Principal Balance
CA	$718,024,311.07	69.95%	CA	$134,219,821.28	53.17%
FL	$44,975,534.75	4.38%	NY	$21,432,410.60	8.49%
NY	$43,747,570.39	4.26%	WA	$8,369,413.71	3.32%
WA	$37,539,181.63	3.66%	FL	$8,316,287.19	3.29%
IL	$36,353,681.91	3.54%	CT	$7,648,081.34	3.03%
OTHER	$145,789,039.51	14.20%	OTHER	$72,448,184.50	28.70%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Prepayment Information (all groups)
	1 Month	3 Month	6 Month	12 Month	Cumulative
PSA	1577.93198%	1707.89689%	1707.89689%	1707.89689%	1707.89689%
CPR	17.25557%	16.98326%	16.98326%	16.98326%	16.98326%
SMM	1.56605%	1.53910%	1.53910%	1.53910%	1.53910%

Trigger Events
	Trigger Flag
Groups I and II Optional Termination Date Has Occurred; 1=Yes, 0=No	0
Group III Optional Termination Date Has Occurred; 1=Yes, 0=No	0
Group IV and Group V Optional Termination Date Has Occurred; 1=Yes, 0=No	0
Groups I and II Senior Prepayment Step-Down Has Occurred; 1=Yes, 0=No	0
Group III Senior Prepayment Step-Down Has Occurred; 1=Yes, 0=No	0
Group IV and Group V Senior Prepayment Step-Down Has Occurred; 1=Yes, 0=No	0
Groups I and II Senior Credit Support Depletion Date Has Occurred; 1=Yes, 0=No	0
Group III Senior Credit Support Depletion Date Has Occurred; 1=Yes, 0=No	0
Group IV and Group V Senior Credit Support Depletion Date Has Occurred; 1=Yes, 0=No	0

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Comments

1. The Class L-B Subordinate Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, to the Group 1 and Group 2 Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated March 22, 2007 to that certain Prospectus, dated March 22, 2007, pursuant to which the certain Senior Certificates were offered.

2. The Group 3-B Subordinate Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, to certain Group 3 Senior Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated March 22, 2007 to that certain Prospectus, dated March 22, 2007, pursuant to which the Group 3 Senior Certificates were offered.

3. The Group M-B Subordinate Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, to certain Group 4 and 5 Senior Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated March 22, 2007 to that certain Prospectus, dated March 22, 2007, pursuant to which the Group 4 and 5 Senior Certificates were offered.

4. The MBA method of delinquency calculation is used.

Certificate Payment Summary Report
Class	CUSIP	Original Principal/Notional Balance	Beginning Principal/Notional Balance	Interest Distribution	Principal Distribution	Principal Loss	Deferred Interest	Total Distribution	Ending Principal/Notional Balance
1A1	933636AA0	$628,059,000.00	$617,810,199.55	$2,869,195.76	$13,678,497.14	$0.00	$0.00	$16,547,692.90	$604,131,702.41
1A2	933636AB8	$30,630,000.00	$30,130,173.14	$139,928.68	$667,090.78	$0.00	$0.00	$807,019.46	$29,463,082.36
2A1	933636AC6	$170,000,000.00	$166,827,183.70	$798,741.53	$2,519,539.68	$0.00	$0.00	$3,318,281.21	$164,307,644.02
2A2	933636AD4	$126,551,000.00	$123,401,289.27	$590,825.39	$2,501,191.50	$0.00	$0.00	$3,092,016.89	$120,900,097.77
2A3	933636AE2	$42,211,000.00	$42,211,000.00	$202,099.44	$0.00	$0.00	$0.00	$202,099.44	$42,211,000.00
2A4	933636AF9	$16,521,000.00	$16,212,658.25	$77,623.58	$244,854.79	$0.00	$0.00	$322,478.37	$15,967,803.46
3A1	933636AG7	$336,830,000.00	$333,230,423.48	$1,628,621.15	$774,872.96	$0.00	$0.00	$2,403,494.11	$332,455,550.52

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Summary Report (Continued)
Class	CUSIP	Original Principal/Notional Balance	Beginning Principal/Notional Balance	Interest Distribution	Principal Distribution	Principal Loss	Deferred Interest	Total Distribution	Ending Principal/Notional Balance
3A2	933636AH5	$27,193,000.00	$26,902,398.56	$131,482.03	$62,557.14	$0.00	$0.00	$194,039.17	$26,839,841.42
4A1	933636AJ1	$108,832,000.00	$106,578,896.27	$490,038.47	$1,415,062.60	$0.00	$0.00	$1,905,101.07	$105,163,833.67
4A2	933636AK8	$6,213,000.00	$6,084,374.84	$27,975.31	$80,783.08	$0.00	$0.00	$108,758.39	$6,003,591.76
5A1	933636AL6	$126,491,000.00	$124,400,742.61	$592,114.26	$4,189,389.82	$0.00	$0.00	$4,781,504.08	$120,211,352.79
5A2	933636AM4	$7,221,000.00	$7,101,673.34	$33,802.07	$239,159.97	$0.00	$0.00	$272,962.04	$6,862,513.37
LB1	933636AN2	$21,801,000.00	$21,800,516.67	$102,342.28	$494.09	$0.00	$0.00	$102,836.37	$21,800,022.58
LB2	933636AP7	$9,571,000.00	$9,570,787.81	$44,929.95	$216.92	$0.00	$0.00	$45,146.87	$9,570,570.89
LB3	933636AQ5	$6,380,000.00	$6,379,858.56	$29,950.18	$144.59	$0.00	$0.00	$30,094.77	$6,379,713.97
LB4	933636AY8	$4,785,000.00	$4,784,893.92	$22,462.63	$108.45	$0.00	$0.00	$22,571.08	$4,784,785.47
LB5	933636AZ5	$4,254,000.00	$4,253,905.69	$19,969.92	$96.41	$0.00	$0.00	$20,066.33	$4,253,809.28
LB6	933636BA9	$2,659,206.29	$2,659,147.34	$12,483.34	$60.27	$0.01	$0.00	$12,543.61	$2,659,087.06
3B1	933636AR3	$6,042,000.00	$6,041,865.86	$29,528.85	$128.49	$0.00	$0.00	$29,657.34	$6,041,737.37
3B2	933636AS1	$2,644,000.00	$2,643,941.30	$12,921.93	$56.23	$0.00	$0.00	$12,978.16	$2,643,885.07

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Summary Report (Continued)
Class	CUSIP	Original Principal/Notional Balance	Beginning Principal/Notional Balance	Interest Distribution	Principal Distribution	Principal Loss	Deferred Interest	Total Distribution	Ending Principal/Notional Balance
3B3	933636AT9	$1,510,000.00	$1,509,966.48	$7,379.77	$32.11	$0.00	$0.00	$7,411.88	$1,509,934.37
3B4	933636BB7	$1,511,000.00	$1,510,966.46	$7,384.66	$32.13	$0.00	$0.00	$7,416.79	$1,510,934.33
3B5	933636BC5	$1,132,000.00	$1,131,974.87	$5,532.38	$24.07	$0.00	$0.00	$5,556.45	$1,131,950.80
3B6	933636BD3	$756,150.06	$756,133.27	$3,695.51	$15.96	$0.12	$0.00	$3,711.47	$756,117.19
MB1	933636AU6	$5,785,000.00	$5,783,481.88	$27,094.91	$1,512.04	$0.00	$0.00	$28,606.95	$5,781,969.84
MB2	933636AV4	$2,893,000.00	$2,892,240.81	$13,549.80	$756.15	$0.00	$0.00	$14,305.95	$2,891,484.66
MB3	933636AW2	$1,577,000.00	$1,576,586.16	$7,386.11	$412.19	$0.00	$0.00	$7,798.30	$1,576,173.97
MB4	933636BE1	$1,710,000.00	$1,709,551.26	$8,009.04	$446.95	$0.00	$0.00	$8,455.99	$1,709,104.31
MB5	933636BF8	$1,314,000.00	$1,313,655.18	$6,154.32	$343.44	$0.00	$0.00	$6,497.76	$1,313,311.74
MB6	933636BG6	$921,345.12	$921,103.34	$4,315.26	$240.77	$0.05	$0.00	$4,556.03	$920,862.52
R	933636AX0	$100.00	$0.00	$0.04	$0.00	$0.00	$0.00	$0.04	$0.00
R_SYN	XXXXXXXXX	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
TFEE	XXXXXXXXX	$0.00	$0.00	$531.41	$0.00	$0.00	$0.00	$531.41	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Summary Report (Continued)
Class	CUSIP	Original Principal/Notional Balance	Beginning Principal/Notional Balance	Interest Distribution	Principal Distribution	Principal Loss	Deferred Interest	Total Distribution	Ending Principal/Notional Balance
Total*		$1,703,997,801.47	$1,678,131,589.87	$7,947,538.53	$26,378,120.72	$0.18	$0.00	$34,325,659.27	$1,651,753,468.97

*Total balances exclude notional balances.

Total Funds Available for Distribution
PRINCIPAL BALANCE
Scheduled Principal Received or Advanced	$99,236.06
Unscheduled Principal	$3,225,011.34
Prepayments in Full	$23,053,873.50
Repurchases	$0.00
Liquidations	$0.00
Total Principal	$26,378,120.90
INTEREST
Accrued Interest at Gross Rate	$8,815,236.19
Relief Act Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Total Funds Available for Distribution
INTEREST
Prepayment Interest Shortfall	$0.00
Servicing Fees	$867,696.88
Other	$0.00
Total Interest	$7,947,538.35
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00
Total Additional Funds	$0.00
Total Funds Available for Distribution	$34,325,659.25

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Principal
Class	CUSIP	Beginning Principal/Notional Balance	Principal Distribution	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal Distribution	Ending Principal/Notional Balance
1A1	933636AA0	$617,810,199.55	$13,678,497.14	$0.00	$0.00	$0.00	$0.00	$13,678,497.14	$604,131,702.41
1A2	933636AB8	$30,130,173.14	$667,090.78	$0.00	$0.00	$0.00	$0.00	$667,090.78	$29,463,082.36
2A1	933636AC6	$166,827,183.70	$2,519,539.68	$0.00	$0.00	$0.00	$0.00	$2,519,539.68	$164,307,644.02
2A2	933636AD4	$123,401,289.27	$2,501,191.50	$0.00	$0.00	$0.00	$0.00	$2,501,191.50	$120,900,097.77
2A3	933636AE2	$42,211,000.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$42,211,000.00
2A4	933636AF9	$16,212,658.25	$244,854.79	$0.00	$0.00	$0.00	$0.00	$244,854.79	$15,967,803.46
3A1	933636AG7	$333,230,423.48	$774,872.96	$0.00	$0.00	$0.00	$0.00	$774,872.96	$332,455,550.52
3A2	933636AH5	$26,902,398.56	$62,557.14	$0.00	$0.00	$0.00	$0.00	$62,557.14	$26,839,841.42
4A1	933636AJ1	$106,578,896.27	$1,415,062.60	$0.00	$0.00	$0.00	$0.00	$1,415,062.60	$105,163,833.67
4A2	933636AK8	$6,084,374.84	$80,783.08	$0.00	$0.00	$0.00	$0.00	$80,783.08	$6,003,591.76
5A1	933636AL6	$124,400,742.61	$4,189,389.82	$0.00	$0.00	$0.00	$0.00	$4,189,389.82	$120,211,352.79
5A2	933636AM4	$7,101,673.34	$239,159.97	$0.00	$0.00	$0.00	$0.00	$239,159.97	$6,862,513.37

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Principal (Continued)
Class	CUSIP	Beginning Principal/Notional Balance	Principal Distribution	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal Distribution	Ending Principal/Notional Balance
LB1	933636AN2	$21,800,516.67	$494.09	$0.00	$0.00	$0.00	$0.00	$494.09	$21,800,022.58
LB2	933636AP7	$9,570,787.81	$216.92	$0.00	$0.00	$0.00	$0.00	$216.92	$9,570,570.89
LB3	933636AQ5	$6,379,858.56	$144.59	$0.00	$0.00	$0.00	$0.00	$144.59	$6,379,713.97
LB4	933636AY8	$4,784,893.92	$108.45	$0.00	$0.00	$0.00	$0.00	$108.45	$4,784,785.47
LB5	933636AZ5	$4,253,905.69	$96.41	$0.00	$0.00	$0.00	$0.00	$96.41	$4,253,809.28
LB6	933636BA9	$2,659,147.34	$60.27	$0.01	$0.00	$0.00	$0.00	$60.27	$2,659,087.06
3B1	933636AR3	$6,041,865.86	$128.49	$0.00	$0.00	$0.00	$0.00	$128.49	$6,041,737.37
3B2	933636AS1	$2,643,941.30	$56.23	$0.00	$0.00	$0.00	$0.00	$56.23	$2,643,885.07
3B3	933636AT9	$1,509,966.48	$32.11	$0.00	$0.00	$0.00	$0.00	$32.11	$1,509,934.37
3B4	933636BB7	$1,510,966.46	$32.13	$0.00	$0.00	$0.00	$0.00	$32.13	$1,510,934.33
3B5	933636BC5	$1,131,974.87	$24.07	$0.00	$0.00	$0.00	$0.00	$24.07	$1,131,950.80
3B6	933636BD3	$756,133.27	$15.96	$0.12	$0.00	$0.00	$0.00	$15.96	$756,117.19
MB1	933636AU6	$5,783,481.88	$1,512.04	$0.00	$0.00	$0.00	$0.00	$1,512.04	$5,781,969.84

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Principal (Continued)
Class	CUSIP	Beginning Principal/Notional Balance	Principal Distribution	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal Distribution	Ending Principal/Notional Balance
MB2	933636AV4	$2,892,240.81	$756.15	$0.00	$0.00	$0.00	$0.00	$756.15	$2,891,484.66
MB3	933636AW2	$1,576,586.16	$412.19	$0.00	$0.00	$0.00	$0.00	$412.19	$1,576,173.97
MB4	933636BE1	$1,709,551.26	$446.95	$0.00	$0.00	$0.00	$0.00	$446.95	$1,709,104.31
MB5	933636BF8	$1,313,655.18	$343.44	$0.00	$0.00	$0.00	$0.00	$343.44	$1,313,311.74
MB6	933636BG6	$921,103.34	$240.77	$0.05	$0.00	$0.00	$0.00	$240.77	$920,862.52
R	933636AX0	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
R_SYN	XXXXXXXXX	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
TFEE	XXXXXXXXX	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total *		$1,678,131,589.87	$26,378,120.72	$0.18	$0.00	$0.00	$0.00	$26,378,120.72	$1,651,753,468.97

*Total balances exclude notional balances.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Interest
Class	Beginning Principal/Notional Balance	Interest Rate Accrued	Interest Rate Paid	Interest Accrued	Prepayment Interest Shortfall	Relief Act Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Total Interest Distributed	Total Carryforward Amount Remaining
1A1	$617,810,199.55	5.5729661574%	5.5729661574%	$2,869,196.11	$0.00	$0.00	$0.00	($0.35)	$0.00	$0.00	$2,869,195.76	$0.00
1A2	$30,130,173.14	5.5729661574%	5.5729661574%	$139,928.70	$0.00	$0.00	$0.00	($0.02)	$0.00	$0.00	$139,928.68	$0.00
2A1	$166,827,183.70	5.7454063505%	5.7454063505%	$798,741.63	$0.00	$0.00	$0.00	($0.10)	$0.00	$0.00	$798,741.53	$0.00
2A2	$123,401,289.27	5.7454063505%	5.7454063505%	$590,825.46	$0.00	$0.00	$0.00	($0.07)	$0.00	$0.00	$590,825.39	$0.00
2A3	$42,211,000.00	5.7454063505%	5.7454063505%	$202,099.46	$0.00	$0.00	$0.00	($0.02)	$0.00	$0.00	$202,099.44	$0.00
2A4	$16,212,658.25	5.7454063505%	5.7454063505%	$77,623.59	$0.00	$0.00	$0.00	($0.01)	$0.00	$0.00	$77,623.58	$0.00
3A1	$333,230,423.48	5.8648474973%	5.8648474973%	$1,628,621.35	$0.00	$0.00	$0.00	($0.20)	$0.00	$0.00	$1,628,621.15	$0.00
3A2	$26,902,398.56	5.8648474973%	5.8648474973%	$131,482.05	$0.00	$0.00	$0.00	($0.02)	$0.00	$0.00	$131,482.03	$0.00
4A1	$106,578,896.27	5.5174734766%	5.5174734766%	$490,038.53	$0.00	$0.00	$0.00	($0.06)	$0.00	$0.00	$490,038.47	$0.00
4A2	$6,084,374.84	5.5174734766%	5.5174734766%	$27,975.31	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$27,975.31	$0.00
5A1	$124,400,742.61	5.7116796519%	5.7116796519%	$592,114.33	$0.00	$0.00	$0.00	($0.07)	$0.00	$0.00	$592,114.26	$0.00
5A2	$7,101,673.34	5.7116796519%	5.7116796519%	$33,802.07	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$33,802.07	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Interest (Continued)
Class	Beginning Principal/Notional Balance	Interest Rate Accrued	Interest Rate Paid	Interest Accrued	Prepayment Interest Shortfall	Relief Act Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Total Interest Distributed	Total Carryforward Amount Remaining
LB1	$21,800,516.67	5.6333873013%	5.6333873013%	$102,342.29	$0.00	$0.00	$0.00	($0.01)	$0.00	$0.00	$102,342.28	$0.00
LB2	$9,570,787.81	5.6333873013%	5.6333873013%	$44,929.96	$0.00	$0.00	$0.00	($0.01)	$0.00	$0.00	$44,929.95	$0.00
LB3	$6,379,858.56	5.6333873013%	5.6333873013%	$29,950.18	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$29,950.18	$0.00
LB4	$4,784,893.92	5.6333873013%	5.6333873013%	$22,462.63	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$22,462.63	$0.00
LB5	$4,253,905.69	5.6333873013%	5.6333873013%	$19,969.92	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$19,969.92	$0.00
LB6	$2,659,147.34	5.6333873013%	5.6333873013%	$12,483.34	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$12,483.34	$0.00
3B1	$6,041,865.86	5.8648474973%	5.8648474973%	$29,528.85	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$29,528.85	$0.00
3B2	$2,643,941.30	5.8648474973%	5.8648474973%	$12,921.93	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$12,921.93	$0.00
3B3	$1,509,966.48	5.8648474973%	5.8648474973%	$7,379.77	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,379.77	$0.00
3B4	$1,510,966.46	5.8648474973%	5.8648474973%	$7,384.66	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,384.66	$0.00
3B5	$1,131,974.87	5.8648474973%	5.8648474973%	$5,532.38	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$5,532.38	$0.00
3B6	$756,133.27	5.8648474973%	5.8648474973%	$3,695.51	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$3,695.51	$0.00
MB1	$5,783,481.88	5.6218543078%	5.6218543078%	$27,094.91	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$27,094.91	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Certificate Payment Report - Interest (Continued)
Class	Beginning Principal/Notional Balance	Interest Rate Accrued	Interest Rate Paid	Interest Accrued	Prepayment Interest Shortfall	Relief Act Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Total Interest Distributed	Total Carryforward Amount Remaining
MB2	$2,892,240.81	5.6218543078%	5.6218543078%	$13,549.80	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$13,549.80	$0.00
MB3	$1,576,586.16	5.6218543078%	5.6218543078%	$7,386.11	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,386.11	$0.00
MB4	$1,709,551.26	5.6218543078%	5.6218543078%	$8,009.04	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$8,009.04	$0.00
MB5	$1,313,655.18	5.6218543078%	5.6218543078%	$6,154.32	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$6,154.32	$0.00
MB6	$921,103.34	5.6218543078%	5.6218543078%	$4,315.26	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,315.26	$0.00
R	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.04	$0.00
R_SYN	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
TFEE	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$531.41	$0.00
Total *	$1,678,131,589.87			$7,947,539.45	$0.00	$0.00	$0.00	($0.96)	$0.00	$0.00	$7,947,538.53	$0.00

*Total balances exclude notional balances.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Principal Factors Report
Class	Original Scheduled Balance	Beginning Principal/Notional Balance	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal	Ending Principal/Notional Balance Percent	Ending Principal/Notional Balance
1A1	$628,059,000.00	983.68178714	0.00000000	0.00000000	0.00000000	0.00000000	21.77900029	0.9619027869	961.90278686
1A2	$30,630,000.00	983.68178714	0.00000000	0.00000000	0.00000000	0.00000000	21.77900033	0.9619027868	961.90278681
2A1	$170,000,000.00	981.33637471	0.00000000	0.00000000	0.00000000	0.00000000	14.82082165	0.9665155531	966.51555306
2A2	$126,551,000.00	975.11113519	0.00000000	0.00000000	0.00000000	0.00000000	19.76429661	0.9553468386	955.34683859
2A3	$42,211,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
2A4	$16,521,000.00	981.33637492	0.00000000	0.00000000	0.00000000	0.00000000	14.82082138	0.9665155535	966.51555354
3A1	$336,830,000.00	989.31337316	0.00000000	0.00000000	0.00000000	0.00000000	2.30048677	0.9870128864	987.01288638
3A2	$27,193,000.00	989.31337329	0.00000000	0.00000000	0.00000000	0.00000000	2.30048689	0.9870128864	987.01288640
4A1	$108,832,000.00	979.29741501	0.00000000	0.00000000	0.00000000	0.00000000	13.00226588	0.9662951491	966.29514913
4A2	$6,213,000.00	979.29741510	0.00000000	0.00000000	0.00000000	0.00000000	13.00226622	0.9662951489	966.29514888
5A1	$126,491,000.00	983.47505048	0.00000000	0.00000000	0.00000000	0.00000000	33.12006246	0.9503549880	950.35498802

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Principal Factors Report (Continued)
Class	Original Scheduled Balance	Beginning Principal/Notional Balance	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal	Ending Principal/Notional Balance Percent	Ending Principal/Notional Balance
5A2	$7,221,000.00	983.47505055	0.00000000	0.00000000	0.00000000	0.00000000	33.12006232	0.9503549882	950.35498823
LB1	$21,801,000.00	999.97782992	0.00000000	0.00000000	0.00000000	0.00000000	0.02266364	0.9999551663	999.95516628
LB2	$9,571,000.00	999.97782990	0.00000000	0.00000000	0.00000000	0.00000000	0.02266430	0.9999551656	999.95516560
LB3	$6,380,000.00	999.97783072	0.00000000	0.00000000	0.00000000	0.00000000	0.02266301	0.9999551677	999.95516771
LB4	$4,785,000.00	999.97783072	0.00000000	0.00000000	0.00000000	0.00000000	0.02266458	0.9999551661	999.95516614
LB5	$4,254,000.00	999.97783028	0.00000000	0.00000000	0.00000000	0.00000000	0.02266338	0.9999551669	999.95516690
LB6	$2,659,206.29	999.97783173	0.00000376	0.00000000	0.00000000	0.00000000	0.02266466	0.9999551633	999.95516331
3B1	$6,042,000.00	999.97779874	0.00000000	0.00000000	0.00000000	0.00000000	0.02126614	0.9999565326	999.95653261
3B2	$2,644,000.00	999.97779879	0.00000000	0.00000000	0.00000000	0.00000000	0.02126702	0.9999565318	999.95653177
3B3	$1,510,000.00	999.97780132	0.00000000	0.00000000	0.00000000	0.00000000	0.02126490	0.9999565364	999.95653642
3B4	$1,511,000.00	999.97780278	0.00000000	0.00000000	0.00000000	0.00000000	0.02126406	0.9999565387	999.95653872
3B5	$1,132,000.00	999.97780035	0.00000000	0.00000000	0.00000000	0.00000000	0.02126325	0.9999565371	999.95653710
3B6	$756,150.06	999.97779541	0.00015870	0.00000000	0.00000000	0.00000000	0.02110692	0.9999565298	999.95652979

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Principal Factors Report (Continued)
Class	Original Scheduled Balance	Beginning Principal/Notional Balance	Principal Loss	Principal Reimbursed	Subsequent Recoveries	Deferred Interest	Total Principal	Ending Principal/Notional Balance Percent	Ending Principal/Notional Balance
MB1	$5,785,000.00	999.73757649	0.00000000	0.00000000	0.00000000	0.00000000	0.26137252	0.9994762040	999.47620398
MB2	$2,893,000.00	999.73757691	0.00000000	0.00000000	0.00000000	0.00000000	0.26137228	0.9994762046	999.47620463
MB3	$1,577,000.00	999.73757768	0.00000000	0.00000000	0.00000000	0.00000000	0.26137603	0.9994762016	999.47620165
MB4	$1,710,000.00	999.73757895	0.00000000	0.00000000	0.00000000	0.00000000	0.26137427	0.9994762047	999.47620468
MB5	$1,314,000.00	999.73757991	0.00000000	0.00000000	0.00000000	0.00000000	0.26136986	0.9994762100	999.47621005
MB6	$921,345.12	999.73757933	0.00005427	0.00000000	0.00000000	0.00000000	0.26132444	0.9994762006	999.47620062
R	$100.00	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000
R_SYN	$0.00	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000
TFEE	$0.00	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Interest Factors Report
Class	Original Balance	Interest Rate Accrued	Interest Rate Paid	Current Month Interest Accrued	Prepayment Interest Shortfall	Relief Act Interest Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Deferred Interest	Total Interest Distribution	Total Carryforward Amount Remaining
1A1	$628,059,000.00	5.5729661574%	5.5729661574%	4.56835442	0.00000000	0.00000000	0.00000000	-0.00000056	0.00000000	0.00000000	0.00000000	4.56835386	0.00000000
1A2	$30,630,000.00	5.5729661574%	5.5729661574%	4.56835455	0.00000000	0.00000000	0.00000000	-0.00000065	0.00000000	0.00000000	0.00000000	4.56835390	0.00000000
2A1	$170,000,000.00	5.7454063505%	5.7454063505%	4.69848018	0.00000000	0.00000000	0.00000000	-0.00000059	0.00000000	0.00000000	0.00000000	4.69847959	0.00000000
2A2	$126,551,000.00	5.7454063505%	5.7454063505%	4.66867476	0.00000000	0.00000000	0.00000000	-0.00000055	0.00000000	0.00000000	0.00000000	4.66867421	0.00000000
2A3	$42,211,000.00	5.7454063505%	5.7454063505%	4.78783872	0.00000000	0.00000000	0.00000000	-0.00000047	0.00000000	0.00000000	0.00000000	4.78783824	0.00000000
2A4	$16,521,000.00	5.7454063505%	5.7454063505%	4.69848012	0.00000000	0.00000000	0.00000000	-0.00000061	0.00000000	0.00000000	0.00000000	4.69847951	0.00000000
3A1	$336,830,000.00	5.8648474973%	5.8648474973%	4.83514340	0.00000000	0.00000000	0.00000000	-0.00000059	0.00000000	0.00000000	0.00000000	4.83514280	0.00000000
3A2	$27,193,000.00	5.8648474973%	5.8648474973%	4.83514324	0.00000000	0.00000000	0.00000000	-0.00000074	0.00000000	0.00000000	0.00000000	4.83514250	0.00000000
4A1	$108,832,000.00	5.5174734766%	5.5174734766%	4.50270628	0.00000000	0.00000000	0.00000000	-0.00000055	0.00000000	0.00000000	0.00000000	4.50270573	0.00000000
4A2	$6,213,000.00	5.5174734766%	5.5174734766%	4.50270562	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.50270562	0.00000000
5A1	$126,491,000.00	5.7116796519%	5.7116796519%	4.68107873	0.00000000	0.00000000	0.00000000	-0.00000055	0.00000000	0.00000000	0.00000000	4.68107818	0.00000000

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Interest Factors Report (Continued)
Class	Original Balance	Interest Rate Accrued	Interest Rate Paid	Current Month Interest Accrued	Prepayment Interest Shortfall	Relief Act Interest Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Deferred Interest	Total Interest Distribution	Total Carryforward Amount Remaining
5A2	$7,221,000.00	5.7116796519%	5.7116796519%	4.68107880	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68107880	0.00000000
LB1	$21,801,000.00	5.6333873013%	5.6333873013%	4.69438512	0.00000000	0.00000000	0.00000000	-0.00000046	0.00000000	0.00000000	0.00000000	4.69438466	0.00000000
LB2	$9,571,000.00	5.6333873013%	5.6333873013%	4.69438512	0.00000000	0.00000000	0.00000000	-0.00000104	0.00000000	0.00000000	0.00000000	4.69438408	0.00000000
LB3	$6,380,000.00	5.6333873013%	5.6333873013%	4.69438558	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.69438558	0.00000000
LB4	$4,785,000.00	5.6333873013%	5.6333873013%	4.69438454	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.69438454	0.00000000
LB5	$4,254,000.00	5.6333873013%	5.6333873013%	4.69438646	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.69438646	0.00000000
LB6	$2,659,206.29	5.6333873013%	5.6333873013%	4.69438571	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.69438571	0.00000000
3B1	$6,042,000.00	5.8648474973%	5.8648474973%	4.88726415	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88726415	0.00000000
3B2	$2,644,000.00	5.8648474973%	5.8648474973%	4.88726551	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88726551	0.00000000
3B3	$1,510,000.00	5.8648474973%	5.8648474973%	4.88726490	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88726490	0.00000000
3B4	$1,511,000.00	5.8648474973%	5.8648474973%	4.88726671	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88726671	0.00000000
3B5	$1,132,000.00	5.8648474973%	5.8648474973%	4.88726148	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88726148	0.00000000
3B6	$756,150.06	5.8648474973%	5.8648474973%	4.88727066	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.88727066	0.00000000

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Interest Factors Report (Continued)
Class	Original Balance	Interest Rate Accrued	Interest Rate Paid	Current Month Interest Accrued	Prepayment Interest Shortfall	Relief Act Interest Shortfall	Other Interest Shortfall	Unscheduled Interest	Interest Reimbursed	Carryforward Amount Paid	Deferred Interest	Total Interest Distribution	Total Carryforward Amount Remaining
MB1	$5,785,000.00	5.6218543078%	5.6218543078%	4.68364909	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68364909	0.00000000
MB2	$2,893,000.00	5.6218543078%	5.6218543078%	4.68365019	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68365019	0.00000000
MB3	$1,577,000.00	5.6218543078%	5.6218543078%	4.68364616	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68364616	0.00000000
MB4	$1,710,000.00	5.6218543078%	5.6218543078%	4.68364912	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68364912	0.00000000
MB5	$1,314,000.00	5.6218543078%	5.6218543078%	4.68365297	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68365297	0.00000000
MB6	$921,345.12	5.6218543078%	5.6218543078%	4.68365209	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.68365209	0.00000000
R	$100.00	0.0000000000%	0.0000000000%	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.40000000	0.00000000
R_SYN	$0.00	0.0000000000%	0.0000000000%	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000
TFEE	$0.00	0.0000000000%	0.0000000000%	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8081
LOAN COUNT
Original Loan Count	883
Beginning Loan Count	872
Loans Added	0
Loans Prepaid-in-full	14
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	858
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$690,812,498.87
Beginning Scheduled Principal Balance	$680,063,059.32
Scheduled Principal Received or Advanced	$15,402.16
Unscheduled Principal	$1,263,343.41
Prepayments-in-full	$13,067,569.87

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8081 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$665,716,743.88
INTEREST
Accrued Interest at Gross Rate	$3,583,347.23
Unscheduled Interest	($0.30)
Uncollected Interest	($9,553.65)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8081 (Continued)
FEES
Servicing Fees	$425,040.16
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8082
LOAN COUNT
Original Loan Count	449
Beginning Loan Count	442
Loans Added	0
Loans Prepaid-in-full	5
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	437
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$372,609,807.42
Beginning Scheduled Principal Balance	$365,978,554.57
Scheduled Principal Received or Advanced	$8,305.61
Unscheduled Principal	$510,538.89
Prepayments-in-full	$4,747,134.69

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8082 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$360,712,575.38
INTEREST
Accrued Interest at Gross Rate	$1,942,860.28
Unscheduled Interest	($0.24)
Uncollected Interest	($2,565.08)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8082 (Continued)
FEES
Servicing Fees	$190,614.04
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8083
LOAN COUNT
Original Loan Count	460
Beginning Loan Count	456
Loans Added	0
Loans Prepaid-in-full	0
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	456
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$377,618,150.06
Beginning Scheduled Principal Balance	$373,727,670.28
Scheduled Principal Received or Advanced	$7,947.91
Unscheduled Principal	$829,771.30
Prepayments-in-full	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8083 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$372,889,951.07
INTEREST
Accrued Interest at Gross Rate	$1,943,336.75
Unscheduled Interest	($0.31)
Uncollected Interest	$0.00
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8083 (Continued)
FEES
Servicing Fees	$116,790.38
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8084
LOAN COUNT
Original Loan Count	295
Beginning Loan Count	292
Loans Added	0
Loans Prepaid-in-full	3
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	289
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$121,612,586.34
Beginning Scheduled Principal Balance	$119,229,571.85
Scheduled Principal Received or Advanced	$23,156.26
Unscheduled Principal	$19,037.54
Prepayments-in-full	$1,454,927.16

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8084 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$117,732,450.89
INTEREST
Accrued Interest at Gross Rate	$616,391.17
Unscheduled Interest	($0.15)
Uncollected Interest	($186.36)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8084 (Continued)
FEES
Servicing Fees	$68,186.23
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8085
LOAN COUNT
Original Loan Count	360
Beginning Loan Count	355
Loans Added	0
Loans Prepaid-in-full	7
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	348
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$141,344,758.78
Beginning Scheduled Principal Balance	$139,132,733.83
Scheduled Principal Received or Advanced	$44,424.12
Unscheduled Principal	$602,320.20
Prepayments-in-full	$3,784,241.78

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8085 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$134,701,747.73
INTEREST
Accrued Interest at Gross Rate	$729,300.76
Unscheduled Interest	$0.04
Uncollected Interest	($6,384.30)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Pool 8085 (Continued)
FEES
Servicing Fees	$67,066.07
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 1
LOAN COUNT
Original Loan Count	1332
Beginning Loan Count	1314
Loans Added	0
Loans Prepaid-in-full	19
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	1295
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$1,063,422,306.29
Beginning Scheduled Principal Balance	$1,046,041,613.89
Scheduled Principal Received or Advanced	$23,707.77
Unscheduled Principal	$1,773,882.30
Prepayments-in-full	$17,814,704.56

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 1 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$1,026,429,319.26
INTEREST
Accrued Interest at Gross Rate	$5,526,207.51
Unscheduled Interest	($0.54)
Uncollected Interest	($12,118.73)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 1 (Continued)
FEES
Servicing Fees	$615,654.20
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 3
LOAN COUNT
Original Loan Count	655
Beginning Loan Count	647
Loans Added	0
Loans Prepaid-in-full	10
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	637
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$262,957,345.12
Beginning Scheduled Principal Balance	$258,362,305.68
Scheduled Principal Received or Advanced	$67,580.38
Unscheduled Principal	$621,357.74
Prepayments-in-full	$5,239,168.94

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 3 (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$252,434,198.62
INTEREST
Accrued Interest at Gross Rate	$1,345,691.93
Unscheduled Interest	($0.11)
Uncollected Interest	($6,570.66)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Group 3 (Continued)
FEES
Servicing Fees	$135,252.30
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Total
LOAN COUNT
Original Loan Count	2447
Beginning Loan Count	2417
Loans Added	0
Loans Prepaid-in-full	29
Loans Liquidated-in-full	0
Loans Repurchased	0
Ending Loan Count	2388
PRINCIPAL BALANCE
Original Scheduled Principal Balance	$1,703,997,801.47
Beginning Scheduled Principal Balance	$1,678,131,589.85
Scheduled Principal Received or Advanced	$99,236.06
Unscheduled Principal	$3,225,011.34
Prepayments-in-full	$23,053,873.50

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Total (Continued)
PRINCIPAL BALANCE
Liquidations-in-full	$0.00
Repurchases	$0.00
Principal Losses	$0.00
Ending Scheduled Principal Balance	$1,651,753,468.95
INTEREST
Accrued Interest at Gross Rate	$8,815,236.19
Unscheduled Interest	($0.96)
Uncollected Interest	($18,689.39)
Relief Act Shortfall	$0.00
Prepayment Interest Shortfall	$0.00
Other Interest Shortfall	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Collateral Report Total (Continued)
FEES
Servicing Fees	$867,696.88
Other Fees	$0.00
ADDITIONAL FUNDS
Excess Liquidation Proceeds	$0.00
Subsequent Recoveries	$0.00
Prepayment Penalties	$0.00
Other	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Delinquency Information by Group*
Group ID	1 Month Count	Scheduled Ending Balance	2 Months Count	Scheduled Ending Balance	3 Months Count	Scheduled Ending Balance	4+ Months Count	Scheduled Ending Balance
Pool 8081	20	$17,162,791.81	0	$0.00	0	$0.00	0	$0.00
Pool 8082	5	$4,153,000.00	0	$0.00	0	$0.00	0	$0.00
Pool 8083	5	$4,130,575.00	0	$0.00	0	$0.00	0	$0.00
Pool 8084	6	$1,772,767.80	4	$1,625,041.44	0	$0.00	0	$0.00
Pool 8085	9	$3,119,310.46	0	$0.00	0	$0.00	0	$0.00
Group 1	25	$21,315,791.81	0	$0.00	0	$0.00	0	$0.00
Group 3	15	$4,892,078.26	4	$1,625,041.44	0	$0.00	0	$0.00
Aggregate	45	$30,338,445.07	4	$1,625,041.44	0	$0.00	0	$0.00

* Does not include mortgage loans in foreclosure or REO.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Foreclosure, REO, and Bankruptcy by Group**
Group ID	Foreclosure Count	Scheduled Ending Balance	REO Count	Scheduled Ending Balance	Bankruptcy Count	Scheduled Ending Balance
Pool 8081	0	$0.00	0	$0.00	0	$0.00
Pool 8082	0	$0.00	0	$0.00	0	$0.00
Pool 8083	0	$0.00	0	$0.00	0	$0.00
Pool 8084	0	$0.00	0	$0.00	0	$0.00
Pool 8085	0	$0.00	0	$0.00	0	$0.00
Group 1	0	$0.00	0	$0.00	0	$0.00
Group 3	0	$0.00	0	$0.00	0	$0.00
Aggregate	0	$0.00	0	$0.00	0	$0.00

** Loans in Bankruptcy will also be reflected under their applicable delinquency or foreclosure status.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Aggregate Loss Amount by Group
Group ID	Count	Loss Amount
Pool 8081	0	$0.00
Pool 8082	0	$0.00
Pool 8083	0	$0.00
Pool 8084	0	$0.00
Pool 8085	0	$0.00
Group 1	0	$0.00
Group 3	0	$0.00
Aggregate	0	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Servicer Advances by Group
Group	Count	Total
Pool 8081	729	$2,723,754.46
Pool 8082	358	$1,431,154.23
Pool 8083	375	$1,496,598.78
Pool 8084	260	$537,537.56
Pool 8085	309	$631,399.94
Group 1	1087	$4,154,908.69
Group 3	569	$1,168,937.50
Aggregate	2031	$6,820,444.97

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Stop Advances Loans
Group	Count	Loan Balance	Total Scheduled P&I
Pool 8081	0	$0.00	$0.00
Pool 8082	0	$0.00	$0.00
Pool 8083	0	$0.00	$0.00
Pool 8084	0	$0.00	$0.00
Pool 8085	0	$0.00	$0.00
Group 1	0	$0.00	$0.00
Group 3	0	$0.00	$0.00
Aggregate	0	$0.00	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Delinquency Roll Rates-Aggregate***
Current Value	Current		1 Month		2 Months		3 Months
Prior Value	Count	Balance	Count	Balance	Count	Balance	Count	Balance
Current	2326	$1,611,537,954.27	40	$28,387,234.33	0	$0.00	0	$0.00
Delq 1 Month	13	$8,252,028.17	5	$1,951,210.74	4	$1,625,041.44	0	$0.00
Delq 2 Month	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Delq 3 Month	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Delq 4 Month	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Foreclosure	0	$0.00	0	$0.00	0	$0.00	0	$0.00

Current Value	4+ Months		Foreclosure		REO
Prior Value	Count	Balance	Count	Balance	Count	Balance
Current	0	$0.00	0	$0.00	0	$0.00
Delq 1 Month	0	$0.00	0	$0.00	0	$0.00
Delq 2 Month	0	$0.00	0	$0.00	0	$0.00
Delq 3 Month	0	$0.00	0	$0.00	0	$0.00
Delq 4 Month	0	$0.00	0	$0.00	0	$0.00
Foreclosure	0	$0.00	0	$0.00	0	$0.00

*** To use this chart, locate along the Current Value row the desired delinquency status as of the immediately preceding due date (e.g. Current, 1 Month delinquent, etc.). Use the left hand column labeled Prior Value to see the prior month's value. Follow the selected Current Value column to the desired Prior Value row.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Credit Enhancement
Type	Original Balance	Beginning Balance	Reduction	Increase	Ending Balance
Over Collateralization	$0.00	$0.00	$0.00	$0.00	$0.00
Reserve Account	$0.00	$0.00	$0.00	$0.00	$0.00
Other	$0.00	$0.00	$0.00	$0.00	$0.00

Insurance
Insurance Type	Original Balance	Claims Paid	Coverage Remaining
Pool Insurance	$0.00	$0.00	$0.00
Other	$0.00	$0.00	$0.00

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Subordinate Class Certificate Balances
The Class Principal Balances of each Class of the Class MB1,MB2,MB3,MB4,MB5,MB6 Certificates immediately after the principal and interest distribution on 05/25/2007 are as follows:
Class	Ending Principal Balance	Percentage of Aggregate Certificate Principal Balance on Closing Date	Percentage of Aggregate Certificate Ending Principal Balance
MB1	$5,781,969.84	0.34%	0.35%
MB2	$2,891,484.66	0.17%	0.18%
MB3	$1,576,173.97	0.09%	0.10%
MB4	$1,709,104.31	0.10%	0.10%
MB5	$1,313,311.74	0.08%	0.08%
MB6	$920,862.52	0.05%	0.06%
Total	$14,192,907.04	0.83%	0.86%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Subordinate Class Certificate Balances
The Class Principal Balances of each Class of the Class 3B1,3B2,3B3,3B4,3B5,3B6 Certificates immediately after the principal and interest distribution on 05/25/2007 are as follows:
Class	Ending Principal Balance	Percentage of Aggregate Certificate Principal Balance on Closing Date	Percentage of Aggregate Certificate Ending Principal Balance
3B1	$6,041,737.37	0.35%	0.37%
3B2	$2,643,885.07	0.16%	0.16%
3B3	$1,509,934.37	0.09%	0.09%
3B4	$1,510,934.33	0.09%	0.09%
3B5	$1,131,950.80	0.07%	0.07%
3B6	$756,117.19	0.04%	0.05%
Total	$13,594,559.13	0.80%	0.82%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Subordinate Class Certificate Balances
The Class Principal Balances of each Class of the Class LB1,LB2,LB3,LB4,LB5,LB6 Certificates immediately after the principal and interest distribution on 05/25/2007 are as follows:
Class	Ending Principal Balance	Percentage of Aggregate Certificate Principal Balance on Closing Date	Percentage of Aggregate Certificate Ending Principal Balance
LB1	$21,800,022.58	1.28%	1.32%
LB2	$9,570,570.89	0.56%	0.58%
LB3	$6,379,713.97	0.37%	0.39%
LB4	$4,784,785.47	0.28%	0.29%
LB5	$4,253,809.28	0.25%	0.26%
LB6	$2,659,087.06	0.16%	0.16%
Total	$49,447,989.25	2.90%	2.99%

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Glossary of Terms
TERM	DEFINITION
Average Ending Scheduled Principal Balance	Average scheduled principal balance of all mortgage loans as of the immediately preceding due date.
Compensating Interest	Interest paid by the servicer or master servicer in respect of Prepayment Interest Shortfall, subject to specified caps.
CPR (Constant Prepayment Rate)	The annualized, compounded single month mortality rate.
Current Interest Accrued	The interest accrued for the current month's distribution.
Deferred Interest	When a scheduled monthly payment is less than required to satisfy the note rate, the unpaid interest is deferred by adding it to the loan balance and the certificate balances.
Excess Liquidation Proceeds	Funds received at the time of liquidation in excess of the amount needed to satisfy the outstanding scheduled principal balance and related expenses.
Interest Rate Accrued	The rate at which interest is accrued for the current month's distribution.
Interest Rate Paid	The rate at which interest is paid for the current month's distribution.
Uncollected Interest	Interest not collected on delinquent loans for which scheduled payments are no longer being advanced, interest uncollected on prepayments and interest uncollected on liquidations.
Other Interest Shortfall	Any interest shortfall other than Uncompensated Interest Shortfall, Deferred Interest or Interest Uncollected on Non-Earning Assets.
Over Collateralization	Any excess of the aggregate principal balance of the mortgage loans over the aggregate principal balance of the certificates.
Prefunding Amount	The amount of cash being held for future loan purchases.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Glossary of Terms (Continued)
TERM	DEFINITION
Prepayment Interest Shortfall	Any shortfall in collections of interest on mortgage loans resulting from prepayments in full or partial prepayments.
Principal Loss	The amount of principal reduction due to a loss realized on the mortgage loans.
Principal Reimbursed	The amount of principal passed through as a reimbursement.
PSA (Prepayment Speed Assumption)	A prepayment model that in its base case (stated as 100% PSA), assumes that prepayments start in month one at an annual CPR of 0.2%, rising linearly to 6.0% CPR in month 30, and then remain flat at 6.0% CPR thereafter.
Relief Act Shortfall	Interest shortfall resulting from application of the Servicemembers Civil Relief Act.
REO (Real Estate Owned)	Property acquired by the trust through foreclosure or deed-in-lieu of foreclosure on a defaulted loan.
Reserve Account	Funded or non-funded accounts set up at either the property or portfolio level in in anticipation of periodic or non-periodic capital expenditures or cash needs.
Servicer Advances	Scheduled principal and interest advances made by the servicer or master servicer for delinquent mortgage loans.
Servicing Fees	The monthly fee paid to the servicer to perform primary servicing function for the master servicer with respect to the mortgage loans and if applicable the fee charged by the master servicer for supervising the mortgage loan servicing.
SMM (Single Month Mortality)	In any given month, the SMM measures the percentage of the beginning pool balance that was paid back earlier than scheduled through payoffs.
Stop Advance	The amount of principal and interest on delinquent mortgage loans for which scheduled payments are no longer being advanced.
Subsequent Recoveries	The amount of funds recovered on mortgage loans that were previously liquidated at a loss.
Trigger Event	An event that may require a change in payment priority.

Series: WAMU 2007-HY4	Washington Mutual
Issue Date: 03/26/2007
Record Date: 04/30/2007
Distribution Date: 05/25/2007

Glossary of Terms (Continued)
TERM	DEFINITION
Unscheduled Interest	Interested collected in addition to the scheduled interest payment.
Unscheduled Principal	Payments of principal which were received with respect to any mortgage loan during the prior period, other than monthly scheduled principal, prepayments in full, repurchases, liquidation principal and subsequent recoveries.
Weighted Average Loan Age	For any distribution date, the weighted average of the loan age on the mortgage loans as of the immediately preceding due date.
Weighted Average Mortgage Interest Rate	For any distribution date, the weighted average of the mortgage interest rates on the mortgage loans as of the second preceding due date (after giving effect to the payments due on the mortgage loans on that due date).
Weighted Average Pass Through Rate	For any distribution date, the weighted average of the pass-through rates on the mortgage loans as of the second preceding due date (after giving effect to the payments due on the mortgage loans on that due date).
Weighted Average Remaining Term	For any distribution date, the weighted average of the maturity on the mortgage loans as of the immediately preceding due date.
MBA Delinquency Calculation	In this calculation, a loan increases its delinquency status if a monthly payment is not received by the end of the day immediately preceding the loan's next due date.
OTS Delinquency Calculation	In this calculation, a loan increases its delinquency status if a monthly payment is not received by the loan's due date in the following month.

WaMu Mortgage Pass-Through Certificates, Series 2007-HY4 10-D