Schedule of Investments (unaudited) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Corporate Bonds
Education — 0.0%
Capital Trust Agency, Inc., RB
8.25%, 01/01/44	$	445	$	8,900
8.25%, 01/01/49		950		19,000
Total Corporate Bonds — 0.0% (Cost: $812,943)				27,900
Municipal Bonds
Alabama — 1.7%
Chelsea Park Cooperative District, SAB, 5.00%, 05/01/48		930		942,726
County of Jefferson Alabama Sewer Revenue, Refunding RB
Series A, Senior Lien, (AGM), 5.00%, 10/01/44		365		383,235
Series D, Sub Lien, 7.00%, 10/01/51		2,355		2,611,008
Series D, Sub Lien, 6.50%, 10/01/53		3,465		3,804,265
Hoover Industrial Development Board, RB, AMT, 6.38%, 11/01/50(a)		7,155		8,739,117
MidCity Improvement District, SAB
3.88%, 11/01/27		130		127,011
4.25%, 11/01/32		350		338,431
4.50%, 11/01/42		745		687,850
4.75%, 11/01/49		795		731,085
Southeast Energy Authority A Cooperative District, RB, Series B, 4.00%, 12/01/51(a)		11,270		12,122,801
Stadium Trace Village Improvement District, RB, 3.63%, 03/01/36		3,860		3,497,928
Tuscaloosa County Industrial Development Authority, Refunding RB, Series A, 4.50%, 05/01/32(b)		1,161		1,188,043
				35,173,500
American Samoa — 0.1%
American Samoa Economic Development Authority, RB, Series A, 5.00%, 09/01/38(b)		1,235		1,432,584
Arizona — 3.3%
Arizona Industrial Development Authority, RB
5.00%, 07/01/45(b)		1,135		1,169,669
7.10%, 01/01/55(b)		4,540		4,182,266
5.00%, 07/01/55(b)		1,215		1,240,773
Class B, 4.00%, 07/01/41		560		563,162
Class B, 4.00%, 07/01/51		1,555		1,523,692
Class B, 4.00%, 07/01/61		3,110		2,960,023
Series A, 5.00%, 07/01/39(b)		1,270		1,301,821
Series A, 5.00%, 12/15/39(b)		150		157,844
Series A, 5.00%, 07/01/49(b)		2,790		2,841,604
Series A, 5.00%, 07/15/49(b)		675		698,028
Series A, 5.00%, 12/15/49(b)		345		358,958
Series A, 4.00%, 07/01/51		1,555		1,520,154
Series A, 5.00%, 07/01/54(b)		1,110		1,127,378
Series A, 4.00%, 07/01/61		3,190		3,039,426
Series B, 5.13%, 07/01/47(b)		420		441,987
Series B, 5.25%, 07/01/51(b)		570		601,076
Arizona Industrial Development Authority, Refunding RB(b)
Series A, 5.00%, 07/01/26		760		786,643
Series A, 5.25%, 07/01/47		3,235		3,372,099
Series A, 5.50%, 07/01/52		2,970		3,136,614

Security	Par (000)		Value
Arizona (continued)
Florence Town, Inc. Industrial Development Authority, RB, 6.00%, 07/01/23(c)	$	1,375	$	1,448,776
Glendale Industrial Development Authority, RB
5.00%, 05/15/41		275		294,578
5.00%, 05/15/56		1,090		1,157,824
Industrial Development Authority of the City of Phoenix, RB 5.00%, 07/01/54		1,330		1,445,917
5.00%, 07/01/59		655		710,382
Series A, 5.00%, 07/01/34(b)		250		252,985
Series A, 6.50%, 07/01/34(b)		465		501,740
Series A, 5.00%, 07/01/36(b)		1,225		1,278,324
Series A, 5.00%, 07/01/39(b)		205		207,373
Series A, 5.00%, 07/01/41(b)		1,685		1,748,479
Series A, 5.00%, 07/01/43		1,445		1,448,022
Series A, 6.75%, 07/01/44(b)		810		886,324
Series A, 5.25%, 07/01/48(b)		1,690		1,709,540
Series A, 5.00%, 07/01/49(b)		320		323,257
Series A, 5.00%, 07/01/54(b)		530		534,567
Industrial Development Authority of the City of Phoenix, Refunding RB(b)
5.00%, 07/01/35		615		636,183
5.00%, 07/01/45		1,500		1,539,850
Series A, 5.00%, 07/01/35		295		305,161
Industrial Development Authority of the County of Pima, RB
5.13%, 07/01/39		700		707,968
5.25%, 07/01/49		870		876,930
Industrial Development Authority of the County of Pima, Refunding RB(b)
4.00%, 06/15/51		3,995		3,654,278
5.00%, 07/01/56		1,300		1,327,225
4.00%, 06/15/57		3,070		2,736,871
La Paz County Industrial Development Authority, RB, 5.88%, 06/15/48(b)		1,340		1,395,682
Maricopa County Industrial Development Authority, RB(b)
5.25%, 10/01/40		1,255		1,374,480
5.50%, 10/01/51		1,255		1,374,777
AMT, 4.00%, 10/15/47		6,500		6,402,429
Tempe Industrial Development Authority, Refunding RB, 4.00%, 12/01/46		1,190		1,141,914
				68,445,053
Arkansas — 1.6%
Arkansas Development Finance Authority, RB(b)
Series A, AMT, 4.50%, 09/01/49		17,755		18,195,910
Series A, AMT, 4.75%, 09/01/49		8,190		8,563,161
University of Arkansas, RB, Series A, 5.00%, 04/01/52(d)		5,000		5,793,850
				32,552,921
California — 7.4%
California Community Choice Financing Authority, RB, Series A, 4.00%, 10/01/52(a)		13,200		13,940,784
California Community Housing Agency, RB, M/F Housing(b)
3.00%, 08/01/56		2,415		1,806,546
Series A, 5.00%, 04/01/49		690		663,959
Series A-2, 4.00%, 08/01/47		4,430		3,850,534

1

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
California (continued)
California County Tobacco Securitization Agency, Refunding RB, Series A, 5.00%, 06/01/36	$	1,665	$	1,666,459
California Educational Facilities Authority, Refunding RB, 2.25%, 04/01/51		9,975		7,820,739
California Housing Finance Agency, RB, M/F Housing
Class A, 3.25%, 08/20/36		8,756		8,727,087
Series 2021-1, Class A, 3.50%, 11/20/35		5,800		5,976,662
California Municipal Finance Authority, ARB, AMT, Senior Lien, 4.00%, 12/31/47		2,560		2,633,060
California Municipal Finance Authority, RB
Series A, 5.50%, 08/01/34(b)		290		298,891
Series A, 6.00%, 08/01/44(b)		655		677,745
Series A, 3.00%, 02/01/46		1,200		1,021,261
Series A, 6.13%, 08/01/49(b)		570		589,974
Series A, 4.00%, 02/01/51		930		962,354
California Municipal Finance Authority, Refunding RB
Series A, 5.00%, 02/01/42		345		373,176
Series A, 3.00%, 11/01/48		2,000		1,836,574
California Public Finance Authority, RB, Series A, 6.25%, 07/01/54(b)		5,270		5,882,669
California School Finance Authority, RB
6.65%, 07/01/33		295		304,991
6.90%, 07/01/43		650		671,453
California Statewide Communities Development Authority, RB(b)
5.25%, 12/01/38		1,420		1,646,794
5.25%, 12/01/48		1,000		1,142,213
California Statewide Communities Development Authority, SAB, Series 2021-A, 4.00%, 09/02/51		2,000		1,935,924
City of San Jose California Hotel Tax Revenue, RB
6.50%, 05/01/36		310		311,007
6.50%, 05/01/42		760		762,395
CMFA Special Finance Agency I, RB, M/F Housing, Series A, 4.00%, 04/01/56(b)		9,320		8,544,557
CMFA Special Finance Agency XII, RB, M/F Housing, 4.38%, 08/01/49(b)		1,845		1,516,869
CMFA Special Finance Agency, RB, M/F Housing, Series A-1, 3.00%, 12/01/56(b)		3,425		2,522,550
CSCDA Community Improvement Authority, RB, M/F Housing(b)
2.65%, 12/01/46		1,990		1,682,412
3.13%, 07/01/56		3,670		2,822,270
3.25%, 07/01/56		1,225		975,324
3.13%, 08/01/56		5,550		4,174,827
4.00%, 08/01/56		5,000		4,433,445
4.00%, 12/01/56		8,815		6,885,097
4.00%, 03/01/57		2,465		1,954,457
3.25%, 05/01/57		1,740		1,360,971
4.00%, 06/01/57		1,445		1,172,406
4.00%, 07/01/58		2,990		2,357,903
Series A, 5.00%, 01/01/54		1,050		1,055,306
Series A-2, 4.00%, 10/01/56		8,600		7,691,771
Series B, 4.00%, 12/01/59		4,645		3,318,750
Senior Lien, 3.00%, 06/01/47		1,510		1,255,194
Series B, Sub Lien, 4.00%, 12/01/59		2,380		1,550,753
Golden State Tobacco Securitization Corp., Refunding RB(c)
Series A-1, 5.00%, 06/01/22		5,195		5,226,835

Security	Par (000)		Value
California (continued)
Golden State Tobacco Securitization Corp., Refunding RB(c) (continued)
Series A-2, 5.00%, 06/01/22	$	3,950	$	3,975,422
Golden State Tobacco Securitization Corp., Refunding RB, CAB, Series B, 0.00%, 06/01/66(e)		78,490		9,570,050
Hastings Campus Housing Finance Authority, RB, CAB, Sub-Series A, 6.75%, 07/01/61(b)(f)		4,420		2,219,145
Los Angeles Department of Water & Power, RB, Series B, 5.00%, 07/01/47(d)		1,275		1,516,935
Riverside County Transportation Commission, RB, Series A, Senior Lien, 5.75%, 06/01/23(c)		2,115		2,214,003
San Francisco City & County Redevelopment Agency Successor Agency, ST, CAB, 0.00%, 08/01/43(e)		3,000		876,462
San Francisco City & County Redevelopment Agency Successor Agency, TA, CAB(b)(e)
Series D, 0.00%, 08/01/23		1,000		945,392
Series D, 0.00%, 08/01/26		580		474,601
Series D, 0.00%, 08/01/31		1,155		738,674
San Mateo Joint Powers Financing Authority, RB, Class A, 3.00%, 06/15/46		7,835		7,167,521
				155,703,153
Colorado — 4.5%
9th Avenue Metropolitan District No.2, GOL, 5.00%, 12/01/48		1,565		1,599,029
Aspen Street Metropolitan District, GOL, Series A, 5.13%, 12/01/50		1,075		986,519
Aurora Crossroads Metropolitan District No.2, GOL
Series A, 5.00%, 12/01/40		1,000		1,037,355
Series A, 5.00%, 12/01/50		500		513,684
Aviation Station North Metropolitan District No.2, GOL
Series A, 5.00%, 12/01/39		750		779,817
Series A, 5.00%, 12/01/48		1,350		1,397,864
Banning Lewis Ranch Metropolitan District No. 8, GOL, 4.88%, 12/01/51(b)		2,335		2,031,135
Brighton Crossing Metropolitan District No.6, GOL, Series A, 5.00%, 12/01/50		500		516,630
Broadway Station Metropolitan District No.2, GOL
Series A, 5.00%, 12/01/35		735		737,816
Series A, 5.13%, 12/01/48		3,925		3,926,260
Bromley Park Metropolitan District No.2, Refunding GOL, Sub-Series B, 6.38%, 12/15/47		937		949,973
Cascade Ridge Metropolitan District, GOL, 5.00%, 12/01/51		3,000		2,706,517
Centerra Metropolitan District No.1, TA, 5.00%, 12/01/47(b)		820		836,099
Clear Creek Transit Metropolitan District No. 2, GOL Series A, 5.00%, 12/01/41		575		584,297
Series A, 5.00%, 12/01/50		1,000		1,007,840
Colorado Educational & Cultural Facilities Authority, RB
5.00%, 12/01/33		450		453,337
5.00%, 12/01/42		545		548,041
Colorado Educational & Cultural Facilities Authority, Refunding RB(b)
5.00%, 12/01/40		115		115,658
5.00%, 12/01/50		155		153,280
5.00%, 12/01/55		180		176,416

S C H E D U L E    O F   I N V E S T M E N T S 2

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Colorado (continued)
Colorado Health Facilities Authority, RB
Series A, 5.00%, 05/15/35	$	1,885	$	1,907,477
Series A, 5.00%, 05/15/44		1,415		1,374,423
Series A, 5.00%, 05/15/49		940		895,705
Series A, 5.00%, 05/15/58		1,980		1,836,759
Colorado Health Facilities Authority, Refunding RB, Series A, 4.00%, 08/01/44		4,620		4,691,504
Colorado High Performance Transportation Enterprise, RB, 5.00%, 12/31/56		2,500		2,608,530
Constitution Heights Metropolitan District, Refunding GOL, 5.00%, 12/01/49		1,260		1,238,705
Copperleaf Metropolitan District No.3, GOL(c)
Series A, 5.00%, 12/01/22		500		527,245
Series A, 5.13%, 12/01/22		1,200		1,266,425
E-470 Public Highway Authority, Refunding RB, Series B, 0.53%, 09/01/39(a)		2,560		2,455,357
Eagle Brook Meadows Metropolitan District No. 3, GOL, Series 2021, 5.00%, 12/01/51		1,600		1,497,224
Fitzsimons Village Metropolitan District No 3, Refunding GOL
Series A-1, 4.00%, 12/01/26		800		775,394
Series A-1, 4.00%, 12/01/41		1,500		1,276,903
Series A-1, 4.25%, 12/01/55		3,095		2,551,020
Green Valley Ranch East Metropolitan District No.6, GOL, Series A, 5.88%, 12/01/50		2,615		2,730,586
Greenways Metropolitan District No. 1, GOL, Series A, 4.63%, 12/01/51		1,580
				1,373,981
Home Place Metropolitan District, GOL, Series A, 5.75%, 12/01/50		2,345		2,368,469
Horizon Metropolitan District No. 2, GOL
4.50%, 12/01/51(b)		1,675		1,419,775
Series A, 4.50%, 12/01/50		1,810		1,551,803
Jefferson Center Metropolitan District No.1, RB
Series A-2, 4.13%, 12/01/40		580		582,583
Series A-2, 4.38%, 12/01/47		1,000		1,004,377
Karl’s Farm Metropolitan District No.2, GOL(b)
Series A, 5.38%, 12/01/40		515		514,896
Series A, 5.63%, 12/01/50		1,350		1,355,015
Longs Peak Metropolitan District, GOL, 5.25%, 12/01/51(b)		5,000		4,526,847
Loretto Heights Community Authority, RB, 4.88%, 12/01/51		2,640		2,341,188
North Holly Metropolitan District, GOL, Series A, 5.50%, 12/01/48		760		771,895
Palisade Metropolitan District No.2, GOL, Subordinate, 7.25%, 12/15/49		2,825		2,738,185
Palisade Park West Metropolitan District, GOL, Series A, 5.13%, 12/01/49		1,500		1,467,742
Pomponio Terrace Metropolitan District, GOL, Series A, 5.00%, 12/01/49		1,450		1,392,594
Prairie Farm Metropolitan District, GOL, Series A, 5.25%, 12/01/48		1,240		1,292,423
Pronghorn Valley Metropolitan District, GOL, Series A, 4.00%, 12/01/51		1,300		1,128,063
Pueblo Urban Renewal Authority, TA, 4.75%, 12/01/45(b)		3,900		3,965,489
Reunion Metropolitan District, RB, Series A, 3.63%, 12/01/44		1,045		839,708
Southlands Metropolitan District No.1, Refunding GO Series A-1, 5.00%, 12/01/37		1,115		1,163,588

Security	Par (000)		Value
Colorado (continued)
Southlands Metropolitan District No.1, Refunding GO (continued)
Series A-1, 5.00%, 12/01/47	$	3,990	$	4,106,277
Sterling Ranch Community Authority Board, RB, Series B, Subordinate, 7.13%, 12/15/50		750		732,138
Thompson Crossing Metropolitan District No.4, Refunding GOL
5.00%, 12/01/39		1,400		1,452,357
5.00%, 12/01/49		1,480		1,519,654
Timberleaf Metropolitan District, GOL, Series A, 5.75%, 12/01/50		1,730		1,747,314
Waters’ Edge Metropolitan District No.2, GOL, 5.00%, 12/01/51		2,595		2,333,901
Westcreek Metropolitan District No.2, GOL, Series A, 5.38%, 12/01/48		800		803,886
Wild Plum Metropolitan District, GOL, Series A, 5.00%, 12/01/49		595		584,944
				93,769,916
Connecticut — 0.6%
Connecticut Housing Finance Authority, Refunding RB, S/F Housing
Series B-1, (FHLMC, FNMA, GNMA), 3.00%, 11/15/49		1,785		1,785,271
Series C-2, AMT, 2.00%, 05/15/30		125		115,073
Series C-2, AMT, 2.05%, 11/15/30		500		457,618
Series C-2, AMT, 2.15%, 11/15/31		400		362,498
Connecticut State Health & Educational Facilities Authority, RB(b)
Series A, 5.00%, 01/01/45		825		867,871
Series A, 5.00%, 01/01/55		1,100		1,146,146
Mohegan Tribal Finance Authority, RB, 7.00%, 02/01/45(b)		3,765		3,867,257
Mohegan Tribe of Indians of Connecticut, RB, Series A, 6.75%, 02/01/45(b)		971		1,000,700
Mohegan Tribe of Indians of Connecticut, Refunding RB, Series C, 6.25%, 02/01/30(b)		2,045		2,213,856
				11,816,290
Delaware — 0.1%
County of Kent, RB, Series A, 5.00%, 07/01/58		1,500		1,595,529
District of Columbia — 1.6%
District of Columbia Tobacco Settlement Financing Corp., RB, Series B, 0.00%, 06/15/46(e)		43,620		7,690,948
District of Columbia Tobacco Settlement Financing Corp., RB, CAB(e)
Series A, 0.00%, 06/15/46		40,740		8,995,922
Series C, 0.00%, 06/15/55		88,900		7,254,133
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, 6.75%, 05/15/40		385		396,074
Metropolitan Washington Airports Authority Dulles Toll Road Revenue, Refunding RB
Series A, 5.00%, 10/01/53		3,830		3,830,000
Series B, Subordinate, 4.00%, 10/01/49		2,170		2,247,072
Metropolitan Washington Airports Authority Dulles Toll Road Revenue, Refunding RB, CAB,
Series B, 2nd Lien, (AGC), 0.00%, 10/01/30(e)		3,005		2,348,104
				32,762,253
Florida — 10.0%
Alachua County Health Facilities Authority, RB, Series A, 5.00%, 12/01/44		1,720		1,788,213

3

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Florida (continued)
Artisan Lakes East Community Development District, SAB
Series 2021-1, 3.13%, 05/01/41	$	475	$	417,669
Series 2021-1, 4.00%, 05/01/51		450		431,561
Series 2021-2, 3.13%, 05/01/41(b)		510		448,445
Series 2021-2, 4.00%, 05/01/52(b)		550		526,222
Boggy Branch Community Development District, SAB, 4.00%, 05/01/51		1,365		1,294,255
Boggy Creek Improvement District, Refunding SAB, Series 2013, 5.13%, 05/01/43		1,180		1,200,184
Brevard County Health Facilities Authority, Refunding RB
4.00%, 11/15/45(b)		4,040		3,915,891
5.00%, 04/01/47(d)		10,000		11,274,510
4.00%, 11/15/55(b)		5,960		5,501,932
Capital Region Community Development District, Refunding SAB, Series A-1, 5.13%, 05/01/39		2,280		2,419,030
Capital Trust Agency, Inc., RB
4.50%, 01/01/35(b)		2,250		2,306,164
5.00%, 06/01/41(b)		220		229,584
5.00%, 07/01/49(b)		1,270		1,344,275
5.00%, 01/01/55(b)		4,350		4,446,361
5.00%, 06/01/56(b)		740		761,655
4.88%, 06/15/56(b)		6,670		6,274,196
Series A, 5.00%, 06/15/49(b)		500		522,469
Series A, 5.00%, 12/15/49		300		308,536
Series A, 5.75%, 06/01/54(b)		1,925		1,964,128
Series A, 5.00%, 12/15/54		260		266,563
Series B, 0.00%, 01/01/35(e)		3,495		1,400,139
Series B, 0.00%, 01/01/60(e)		64,500		3,526,086
Capital Trust Agency, Inc., RB, CAB, 0.00%, 07/01/61(b)(e)		166,025		11,904,491
Celebration Pointe Community Development District, SAB
4.00%, 05/01/22(b)		75		75,057
4.75%, 05/01/24		165		168,102
5.00%, 05/01/34		1,180		1,210,003
Charles Cove Community Development District, SAB
3.25%, 05/01/25		275		273,672
3.75%, 05/01/30		360		355,347
4.25%, 05/01/40		975		965,076
4.38%, 05/01/50		1,505		1,460,604
Charlotte County Industrial Development Authority, RB(b)
AMT, 5.00%, 10/01/34		530		558,373
AMT, 5.00%, 10/01/49		2,510		2,569,833
AMT, 4.00%, 10/01/51		3,150		2,874,069
City of Tallahassee Florida, RB, Series A, 5.00%, 12/01/55		2,600		2,784,262
Collier County Health Facilities Authority, RB, Series A, 5.00%, 05/01/48		2,090		2,275,239
Collier County Industrial Development Authority, Refunding RB, Series A, 8.13%, 05/15/44(b)(g)(h)		370		252,757
County of Lake Florida, RB(b)
5.00%, 01/15/39		550		581,951
5.00%, 01/15/49		825		859,993
5.00%, 01/15/54		830		862,483
County of Osceola Florida Transportation Revenue, Refunding RB, Sereis A-1, 4.00%, 10/01/54		2,500		2,532,127

Security	Par (000)		Value
Florida (continued)
County of Osceola Florida Transportation Revenue, Refunding RB, CAB(e)
Series A-2, 0.00%, 10/01/50	$	1,770	$	542,395
Series A-2, 0.00%, 10/01/51		2,125		625,056
Series A-2, 0.00%, 10/01/52		2,125		600,208
Series A-2, 0.00%, 10/01/53		5,675		1,533,958
Series A-2, 0.00%, 10/01/54		2,125		549,238
County of Palm Beach Florida, RB, 5.00%, 04/01/51(b)		540		577,664
Escambia County Health Facilities Authority, Refunding RB, 4.00%, 08/15/45		6,530		6,670,369
Florida Development Finance Corp., RB
5.00%, 06/15/41(b)		1,245		1,284,542
5.00%, 06/15/51(b)		1,190		1,214,209
5.25%, 06/01/55(b)		2,830		3,021,583
Series A, 5.75%, 06/15/29		695		730,769
Series A, 6.00%, 06/15/34		835		880,873
Series A, 6.13%, 06/15/44		3,185		3,345,062
Series A, 5.13%, 06/15/55(b)		10,455		9,670,865
Series B, 4.50%, 12/15/56(b)		5,945		4,948,053
Series C, 5.75%, 12/15/56(b)		2,030		1,735,187
AMT, 5.00%, 05/01/29(b)		3,300		3,433,303
AMT, 3.00%, 06/01/32		915		874,183
Series A, AMT, 5.00%, 08/01/29(a)(b)		2,240		2,251,200
Florida Development Finance Corp., Refunding RB
1.75%, 06/01/26(b)		485		461,173
2.38%, 06/01/27(b)		395		381,144
5.00%, 06/01/51		1,135		1,236,595
4.00%, 06/01/55(b)		1,450		1,392,254
Gracewater Sarasota Community Development District, SAB, 4.00%, 05/01/52		1,000		961,601
Grand Oaks Community Development District, SAB
4.25%, 05/01/40		915		905,687
4.50%, 05/01/52		1,015		1,001,088
Greater Orlando Aviation Authority, Refunding RB, AMT, 5.00%, 11/15/36		2,000		2,049,104
Greeneway Improvement District, SAB, 5.13%, 05/01/43		940		954,637
Hills Minneola Community Development District, SAB(b)
4.00%, 05/01/40		1,025		1,031,638
4.00%, 05/01/50		1,500		1,466,284
Lakewood Ranch Stewardship District, SAB
4.25%, 05/01/25		80		81,199
4.25%, 05/01/26		165		167,943
4.95%, 05/01/29(b)		605		641,063
2.70%, 05/01/31		205		193,115
4.88%, 05/01/35		265		272,245
3.75%, 05/01/39(b)		570		551,483
5.50%, 05/01/39(b)		610		665,311
3.75%, 05/01/40		525		524,405
3.00%, 05/01/41		155		135,647
4.88%, 05/01/45		545		555,922
5.13%, 05/01/46		945		977,740
5.65%, 05/01/48(b)		1,025		1,113,127
4.00%, 05/01/49(b)		355		341,018
3.90%, 05/01/50		525		517,736
4.00%, 05/01/52		685		665,025
Series 1A, 3.90%, 05/01/23		100		100,470

S C H E D U L E    O F   I N V E S T M E N T S 4

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Florida (continued)
Lakewood Ranch Stewardship District, SAB (continued)
Series 1A, 4.25%, 05/01/28	$	535	$	548,653
Series 1A, 5.00%, 05/01/38		1,175		1,238,895
Series 1A, 5.10%, 05/01/48		2,545		2,662,375
Series 1B, 4.75%, 05/01/29		955		1,003,031
Series 1B, 5.30%, 05/01/39		1,090		1,175,524
Series 1B, 5.45%, 05/01/48		1,935		2,077,921
Laurel Road Community Development District, SAB
Series A-1, 2.60%, 05/01/26		230		224,619
Series A-1, 3.00%, 05/01/31		250		236,334
Series A-1, 3.25%, 05/01/41		1,010		888,281
Series A-1, 4.00%, 05/01/52		1,155		1,081,096
Series A-2, 3.13%, 05/01/31		1,695		1,578,987
Miami Beach Health Facilities Authority, RB, 3.00%, 11/15/51		4,710		3,711,070
Miami-Dade County Industrial Development Authority, RB, 5.00%, 01/15/48		1,405		1,487,873
Midtown Miami Community Development District, Refunding SAB
Series A, 5.00%, 05/01/29		1,745		1,767,758
Series A, 5.00%, 05/01/37		890		899,922
Mirada II Community Development District, SAB
3.13%, 05/01/31		500		480,584
4.00%, 05/01/51		1,500		1,438,977
North River Ranch Community Development District, SAB
Series A-1, 4.00%, 05/01/40		845		810,109
Series A-1, 4.25%, 05/01/51		1,430		1,355,872
Series A-2, 4.20%, 05/01/35		1,220		1,172,391
Series A-3, 4.75%, 05/01/40		1,615		1,552,109
Palm Beach County Health Facilities Authority, Refunding RB, Series A, 7.50%, 06/01/49		1,000		1,028,138
Pine Island Community Development District, RB, CAB, 0.00%, 11/01/24(e)		625		564,820
Pinellas County Industrial Development Authority, RB, 5.00%, 07/01/39		220		229,819
Sandridge Community Development District, SAB
Series A1, 3.88%, 05/01/41		615		569,873
Series A1, 4.00%, 05/01/51		600		535,319
Series A-2, 3.88%, 05/01/31		635		600,060
Santa Rosa Bay Bridge Authority, RB, 6.25%, 07/01/28(g)(h)		330
				301,915
Sawyers Landing Community Development District, SAB
4.13%, 05/01/41		530		535,750
4.25%, 05/01/53		3,520		3,529,469
Seminole County Industrial Development Authority, Refunding RB, 5.75%, 11/15/54		2,420		2,483,610
South Broward Hospital District, RB, 3.00%, 05/01/51		5,145		4,588,717
Southern Groves Community Development District No.5, SAB
3.38%, 05/01/25		135		135,889
4.00%, 05/01/30		180		185,964
4.30%, 05/01/40		860		877,899
4.50%, 05/01/46		605		615,255

Security	Par (000)		Value
Florida (continued)
Tolomato Community Development District, Refunding SAB
Series 2015-2, 6.61%, 05/01/40(f)	$	125	$	95,123
Series A-2, 4.25%, 05/01/37		910		933,217
Tolomato Community Development District, Refunding SAB, CAB, Series A-4, Convertible, 6.61%, 05/01/40(f)		50		49,848
Tolomato Community Development District, SAB(g)(h)
3rd Series, 6.65%, 05/01/40		105		1
Series 2015-3, 6.61%, 05/01/40		135		1
Trout Creek Community Development District, SAB
5.38%, 05/01/38		670		710,765
5.50%, 05/01/49		1,700		1,789,714
V-Dana Community Development District, SAB(b)
Series 1, Class AR, 3.00%, 05/01/25		230		229,066
Series 1, Class AR, 3.50%, 05/01/31		525		518,039
Series 1, Class AR, 4.00%, 05/01/40		750		748,715
Series 1, Class AR, 4.00%, 05/01/51		1,200		1,151,182
Viera East Community Development District, Refunding SAB, 5.00%, 05/01/26		640		641,329
Viera Stewardship District, SAB, Series 2021, 4.00%, 05/01/53		1,710		1,631,340
Village Community Development District No.10, SAB, 5.13%, 05/01/43		1,450		1,451,995
Village Community Development District No.9, SAB, 5.50%, 05/01/42		440		440,817
West Villages Improvement District, SAB
4.25%, 05/01/29		400		406,342
4.75%, 05/01/39		885		911,177
5.00%, 05/01/50		1,415		1,456,186
Windward at Lakewood Ranch Community Development District, SAB
3.25%, 05/01/27		700		689,151
3.63%, 05/01/32		835		808,817
4.00%, 05/01/42		730		691,720
4.25%, 05/01/52		880		832,849
				209,327,150
Georgia — 1.7%
Atlanta Urban Redevelopment Agency, RB, 3.88%, 07/01/51(b)		2,805		2,607,665
Gainesville & Hall County Hospital Authority, Refunding RB, Series A, (GTD), 5.50%, 02/15/25(c)		555		609,486
Main Street Natural Gas Inc., RB
Series A, 5.00%, 05/15/35		1,020		1,200,030
Series A, 5.00%, 05/15/36		1,020		1,208,218
Series A, 5.00%, 05/15/37		1,120		1,334,208
Series A, 5.00%, 05/15/38		615		736,274
Series A, 5.00%, 05/15/49		2,055		2,521,421
Series C, 4.00%, 05/01/52(a)		2,430		2,536,898
Series C, RB, 4.00%, 03/01/50(a)		5,780		6,009,275
Municipal Electric Authority of Georgia, RB 4.00%, 01/01/49		4,150		4,102,204
Series A, 5.00%, 01/01/49		3,235		3,542,150
Series A, 5.00%, 01/01/59		525		575,307
Municipal Electric Authority of Georgia, Refunding RB
Series A-R, Subordinate, 5.00%, 01/01/45		3,000		3,397,125

5

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Georgia (continued)
Municipal Electric Authority of Georgia, Refunding RB (continued)
Series A-R, Subordinate, 5.00%, 01/01/50	$	4,000	$	4,493,528
Private Colleges & Universities Authority, Refunding RB, 4.00%, 10/01/50		1,155		1,197,338
				36,071,127
Guam — 0.1%
Territory of Guam, Refunding RB, Series A, 5.00%, 11/01/35		1,100		1,250,187
Idaho — 0.4%
Idaho Health Facilities Authority, Refunding RB
3.50%, 09/01/33		375		384,055
5.00%, 09/01/37		1,000		1,080,426
3.00%, 03/01/51		2,835		2,371,211
Idaho Housing & Finance Association, RB(b)
5.00%, 12/01/46		1,000		1,043,107
Series A, 6.00%, 07/01/39		370		418,797
Series A, 6.00%, 07/01/49		595		664,986
Series A, 6.00%, 07/01/54		570		634,594
Series A, 6.95%, 06/15/55		1,540		1,581,389
Power County Industrial Development Corp., RB, AMT, 6.45%, 08/01/32		265		265,830
				8,444,395
Illinois — 5.5%
Chicago Board of Education, GO
Series A, 5.00%, 12/01/38		655		711,313
Series A, 5.00%, 12/01/39		4,845		5,269,940
Series A, 5.00%, 12/01/42		1,570		1,590,468
Series A, 4.00%, 12/01/47		4,905		4,814,831
Series C, 5.25%, 12/01/39		2,250		2,356,135
Series D, 5.00%, 12/01/46		3,620		3,759,309
Series H, 5.00%, 12/01/46		725		766,506
Chicago Board of Education, Refunding GO
Series A, 5.00%, 12/01/30		2,210		2,417,985
Series B, 4.00%, 12/01/35		1,155		1,161,581
Series C, 5.00%, 12/01/25		1,220		1,301,089
Series C, 5.00%, 12/01/30		1,370		1,480,207
Series D, 5.00%, 12/01/31		1,500		1,618,209
Series G, 5.00%, 12/01/44		3,700		3,943,038
Chicago Board of Education, Refunding GO, CAB, Series A, 0.00%, 12/01/25(e)		590		531,283
Chicago Transit Authority Sales Tax Receipts Fund, Refunding RB, Series A, 2nd Lien, 5.00%, 12/01/52		5,550		6,280,519
City of Chicago IL, Refunding GO, Series A, 4.00%, 01/01/36		6,335		6,366,903
Illinois Finance Authority, RB, Series A, 6.00%, 10/01/48		1,700		1,726,996
Illinois Finance Authority, Refunding RB
6.00%, 02/01/34		335		344,767
4.00%, 09/01/35		1,000		1,041,432
4.00%, 09/01/37		1,000		1,025,663
4.00%, 09/01/39		2,000		2,039,680
4.00%, 09/01/41		1,250		1,274,883
6.13%, 02/01/45		790		807,280
5.00%, 05/15/56		815		856,877
Series A, 3.00%, 08/15/48		6,350		5,575,256
Series C, 5.00%, 02/15/36		1,805		1,996,261

Security	Par (000)		Value
Illinois (continued)
Illinois Finance Authority, Refunding RB (continued) Series C, 5.00%, 02/15/41	$	3,000	$	3,278,382
Illinois State Toll Highway Authority, RB
Series A, 4.00%, 01/01/46		2,490		2,622,137
Series A, 5.00%, 01/01/46		6,480		7,511,862
Metropolitan Pier & Exposition Authority, RB
Series A, 5.50%, 06/15/53		3,925		4,116,689
Series A, 5.00%, 06/15/57		4,555		4,753,794
Metropolitan Pier & Exposition Authority, Refunding RB, 4.00%, 06/15/52		6,325		6,229,100
Quad Cities Regional Economic Development Authority, Refunding RB, 4.75%, 10/01/32		675		681,864
Sales Tax Securitization Corp., Refunding RB, Series A, 5.00%, 01/01/33		2,775		3,289,010
State of Illinois, GO
5.50%, 05/01/30		1,235		1,410,156
5.00%, 02/01/39		510		534,786
5.50%, 05/01/39		2,460		2,797,364
Series A, 5.00%, 12/01/25		3,000		3,247,017
Series A, 5.00%, 04/01/35		1,460		1,501,854
Series A, 4.00%, 03/01/38		2,250		2,293,110
Series A, 5.00%, 04/01/38		2,190		2,252,781
Series A, 4.00%, 03/01/39		2,100		2,136,693
Series A, 4.00%, 03/01/40		2,300		2,338,376
State of Illinois, Refunding GO, Series A, 5.00%, 10/01/25		3,000		3,239,601
				115,292,987
Indiana — 0.7%
City of Valparaiso Indiana, RB
AMT, 6.75%, 01/01/34		525		567,171
AMT, 7.00%, 01/01/44		1,270		1,368,633
City of Vincennes Indiana, Refunding RB, 6.25%, 01/01/29(b)		2,325		2,327,755
Indiana Finance Authority, RB
Series A, AMT, 5.00%, 07/01/23(c)		1,600		1,656,714
Series A, AMT, 5.25%, 07/01/23(c)		2,500		2,596,983
Series A, AMT, 6.75%, 05/01/39		2,785		3,432,292
Indiana Housing & Community Development
Authority, RB, 5.38%, 10/01/40(b)		3,175		3,131,274
				15,080,822
Iowa — 0.3%
Iowa Finance Authority, RB, Series A, 5.00%, 05/15/48		2,360		2,427,909
Iowa Finance Authority, Refunding RB, Series A, 5.25%, 12/01/50(a)		595		617,807
Iowa Higher Education Loan Authority, Refunding RB, 5.50%, 11/01/51		3,000		3,144,093
				6,189,809
Kansas — 0.3%
City of Manhattan KS, RB, Series A, 4.00%, 06/01/52		1,360		1,294,772
City of Prairie Village Kansas, Refunding TA
2.88%, 04/01/30		815		758,868
3.13%, 04/01/36		1,000		891,278
City of Shawnee Kansas, RB(b)
5.00%, 08/01/41		770		785,597
5.00%, 08/01/56		1,900		1,918,567
				5,649,082

S C H E D U L E    O F   I N V E S T M E N T S 6

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Kentucky — 0.4%
City of Hazard, Refunding RB, 3.00%, 07/01/46	$	2,500	$	2,130,745
City of Henderson KY, RB, AMT, 4.70%, 01/01/52(b)(d)		1,940		1,950,794
Kentucky Economic Development Finance Authority, Refunding RB, Series B, (NPFGC), 0.00%, 10/01/24(e)		250		236,405
Kentucky Public Transportation Infrastructure Authority, RB, Series A, 6.00%, 07/01/23(c)		3,000		3,150,042
				7,467,986
Louisiana — 1.1%
Juban Crossing Economic Development District, Refunding RB, Series C, 7.00%, 09/15/44(b)		3,010		2,713,226
Louisiana Local Government Environmental Facilities & Community Development Authority, RB, 5.00%, 07/01/54(b)		1,990		1,992,141
Louisiana Public Facilities Authority, RB(b)
Series A, 5.00%, 06/01/41		990		997,525
Series A, 5.00%, 04/01/49		500		506,513
Series A, 5.25%, 06/01/51		1,830		1,855,519
Series A, 5.25%, 06/01/60		3,385		3,410,841
Louisiana Public Facilities Authority, Refunding RB, 4.00%, 04/01/50		8,320		8,659,648
Parish of St. James Louisiana, RB, 2nd Series, 6.35%, 07/01/40(b)		3,160		3,909,716
				24,045,129
Maine — 0.1%
Finance Authority of Maine, RB, AMT, 8.00%, 12/01/51(b)		4,050		3,240,170
Maryland — 1.1%
City of Baltimore Maryland, Refunding RB 5.00%, 09/01/46		1,500		1,479,364
Series A, 4.00%, 09/01/27		325		341,889
County of Frederick Maryland, Refunding TA, 4.63%, 07/01/43(b)		4,965		5,455,612
Maryland Economic Development Corp., RB, 5.00%, 07/01/56		985		1,080,277
Maryland Economic Development Corp., Refunding RB, 5.00%, 07/01/39		950		987,048
Maryland Economic Development Corp., TA, 4.00%, 09/01/50		605		580,062
Maryland Health & Higher Educational Facilities Authority, RB, Series A, 7.00%, 03/01/55(b)		8,165		8,873,444
Maryland State Transportation Authority, Refunding RB, Series A, 2.50%, 07/01/47		2,750		2,249,665
Montgomery County Housing Opportunities Commission, RB, M/F Housing, Series C, (FHA 542(C)), 2.85%, 01/01/51		1,855		1,576,310
				22,623,671
Massachusetts — 0.7%
Massachusetts Development Finance Agency, RB 4.00%, 06/01/56		1,570		1,574,555
Series D, 4.00%, 07/01/45		715		730,436
Massachusetts Development Finance Agency, Refunding RB
4.00%, 10/01/32(b)		355		376,799
4.13%, 10/01/42(b)		855		905,976
4.00%, 07/01/45		560		576,266
4.00%, 07/01/50		1,050		1,072,081
Series A, 5.00%, 07/01/38		1,200		1,340,040

Security	Par (000)		Value
Massachusetts (continued)
Massachusetts Development Finance Agency, Refunding RB (continued)
Series A, 5.00%, 07/01/39	$	3,055	$	3,403,432
Series A, 5.00%, 07/01/44		2,000		2,203,798
Series B, 4.00%, 06/01/50		2,120		2,139,447
				14,322,830
Michigan — 0.5%
Advanced Technology Academy, Refunding RB
3.50%, 11/01/24		190		189,204
5.00%, 11/01/34		400		416,069
5.00%, 11/01/44		160		163,815
City of Detroit Michigan, GO
5.00%, 04/01/34		485		537,502
5.00%, 04/01/35		485		536,304
5.00%, 04/01/36		340		375,006
5.00%, 04/01/37		545		599,633
5.00%, 04/01/38		240		263,281
Grand Traverse County Hospital Finance Authority, Refunding RB, 3.00%, 07/01/51		2,000		1,765,140
Kentwood Economic Development Corp., Refunding RB, 5.63%, 11/15/41		1,000		1,004,582
Michigan Finance Authority, RB(c)
Series C-2, AMT, Senior Lien, 5.00%, 07/01/22		350		353,394
Series C-1, Senior Lien, 5.00%, 07/01/22		800		807,798
Michigan Strategic Fund, RB
AMT, 5.00%, 06/30/48		2,030		2,192,351
AMT, 4.00%, 10/01/61(a)		1,355		1,428,781
				10,632,860
Minnesota — 0.7%
City of Cologne Minnesota,RB, Series A, 5.00%, 07/01/45		2,065		2,099,952
City of Deephaven Minnesota, Refunding RB, Series A, 5.25%, 07/01/40		500		518,003
City of Minneapolis Minnesota, RB
Series A, 5.00%, 07/01/55		1,405		1,408,980
Series A, 5.75%, 07/01/55		3,435		3,762,222
Duluth Economic Development Authority, Refunding RB
Series A, 4.25%, 02/15/48		1,925		2,032,952
Series A, 5.25%, 02/15/53		3,850		4,319,327
				14,141,436
Mississippi — 0.3%
Mississippi Home Corp., Refunding RB, S/F Housing, Series B, (FHLMC, FNMA, GNMA), 2.10%, 12/01/41		8,025		6,907,037
Missouri — 0.7%
Health & Educational Facilities Authority of the State of Missouri, Refunding RB, Series A, 4.00%, 11/15/48		3,650		3,787,437
Industrial Development Authority of the City of St. Louis Missouri, Refunding RB
Series A, 4.38%, 11/15/35		1,020		972,912
Series A, 4.75%, 11/15/47		1,135		990,786
Kansas City Industrial Development Authority, RB, Series C, 7.50%, 11/15/46		425		389,105
Kansas City Industrial Development Authority, Refunding RB
2.00%, 11/15/46		345		16,688
5.00%, 11/15/46		772		697,152

7

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Missouri (continued)
Kansas City Land Clearance Redevelopment Authority, TA(b)
Series B, 4.38%, 02/01/31	$	3,105	$	2,908,233
Series B, 5.00%, 02/01/40		1,240		1,140,582
Plaza at Noah’s Ark Community Improvement District, Refunding RB
3.00%, 05/01/25		350		350,363
3.00%, 05/01/26		275		274,434
3.00%, 05/01/30		475		460,283
3.13%, 05/01/35		500		463,917
Poplar Bluff Regional Transportation Development District, RB, 4.75%, 12/01/42		2,200		2,234,181
				14,686,073
Nebraska — 0.4%
Central Plains Energy Project, RB, 5.00%, 09/01/42		780		791,131
Central Plains Energy Project, Refunding RB, Series A, 5.00%, 09/01/42		6,090		7,235,962
				8,027,093
Nevada — 0.2%
City of Las Vegas Nevada Special Improvement District No.815, SAB, 5.00%, 12/01/49		810		869,545
County of Clark Nevada, Refunding SAB
4.00%, 08/01/22		375		378,296
4.00%, 08/01/23		230		231,946
Tahoe-Douglas Visitors Authority, RB
5.00%, 07/01/40		825		907,293
5.00%, 07/01/45		1,025		1,111,813
5.00%, 07/01/51		1,100		1,180,192
				4,679,085
New Hampshire — 0.6%
New Hampshire Business Finance Authority, RB
Series A, 4.13%, 08/15/40		1,435		1,346,077
Series A, 4.25%, 08/15/46		1,610		1,483,105
Series A, 4.50%, 08/15/55		3,350		3,092,874
New Hampshire Business Finance Authority, Refunding RB(b)
Series B, 4.63%, 11/01/42		4,650		4,754,792
Series C, AMT, 4.88%, 11/01/42		2,515		2,579,266
				13,256,114
New Jersey — 3.8%
Casino Reinvestment Development Authority, Inc., Refunding RB, 5.25%, 11/01/44		5,750		6,081,234
Industrial Pollution Control Financing Authority of Gloucester County, Refunding RB, Series A, AMT, 5.00%, 12/01/24		880		922,251
New Jersey Economic Development Authority, RB
4.00%, 11/01/39		1,165		1,196,555
6.00%, 10/01/43		970		1,018,839
Series A, 5.00%, 07/01/32		235		246,309
Series A, 5.00%, 07/01/37		375		390,004
Series A, 5.25%, 11/01/54(b)		3,955		3,945,749
Series B, 5.00%, 06/15/43		3,755		4,104,591
Series EEE, 5.00%, 06/15/43		5,550		6,066,705
AMT, 5.13%, 09/15/23		1,045		1,062,649
AMT, 5.38%, 01/01/43		1,360		1,409,663
Series B, AMT, 6.50%, 04/01/31		2,585		2,818,539

Security	Par (000)		Value
New Jersey (continued)
New Jersey Health Care Facilities Financing Authority, RB, 3.00%, 07/01/51	$	10,160	$	9,299,133
New Jersey Health Care Facilities Financing Authority, Refunding RB
5.00%, 07/01/32		1,140		1,263,912
5.00%, 07/01/33		1,450		1,605,033
New Jersey Higher Education Student Assistance Authority, RB
Series B, AMT, 2.50%, 12/01/40		3,660		3,434,273
Series C, AMT, 3.25%, 12/01/51		1,700		1,494,898
New Jersey Transportation Trust Fund Authority, RB
Series A, 0.00%, 12/15/40(e)		7,560		3,647,919
Series AA, 5.25%, 06/15/41		1,265		1,340,693
Series AA, 5.00%, 06/15/44		1,005		1,037,783
Series BB, 4.00%, 06/15/50		10,940		11,135,060
Series BB, 5.00%, 06/15/50		8,560		9,335,476
Series S, 5.25%, 06/15/43		4,095		4,537,547
New Jersey Transportation Trust Fund Authority, Refunding RB, Series A, 5.00%, 12/15/36		1,195		1,318,608
South Jersey Port Corp., ARB, Series B, AMT, 5.00%, 01/01/36		575		626,269
Tobacco Settlement Financing Corp., Refunding RB, Series A, 5.25%, 06/01/46		900		977,303
				80,316,995
New Mexico — 0.5%
New Mexico Hospital Equipment Loan Council, Refunding RB, 5.50%, 07/01/42		2,030		2,045,442
New Mexico Mortgage Finance Authority, RB, S/F Housing, (FHLMC, FNMA, GNMA), 3.00%, 01/01/52		7,700		7,717,210
				9,762,652
New York — 7.3%
Albany Capital Resource Corp., Refunding RB, 4.00%, 07/01/41		3,750		3,710,344
Build NYC Resource Corp., Refunding RB, AMT, 5.00%, 01/01/35(b)		1,215		1,297,780
Chautauqua Tobacco Asset Securitization Corp., Refunding RB, 5.00%, 06/01/48		4,475		4,605,142
Huntington Local Development Corp., RB, Series A, 5.25%, 07/01/56		585		609,685
Metropolitan Transportation Authority, Refunding RB
Series C-1, 4.75%, 11/15/45		4,115		4,475,359
Series C-1, 5.00%, 11/15/50		1,340		1,477,736
Series C-1, 5.25%, 11/15/55		1,980		2,207,981
Monroe County Industrial Development Corp., Refunding RB, 4.00%, 12/01/39		1,200		1,258,426
New York City Industrial Development Agency, Refunding RB
Series A, Class A, (AGM), 3.00%, 01/01/37		755		700,435
Series A, Class A, (AGM), 3.00%, 01/01/39		755		695,118
Series A, Class A, (AGM), 3.00%, 01/01/40		525		481,372
New York City Transitional Finance Authority Future Tax Secured Revenue, RB(d)
Series F-1, Subordinate, 5.00%, 02/01/47		2,500		2,862,925
Series F-1, Subordinate, 5.00%, 02/01/51		4,495		5,131,177
New York Counties Tobacco Trust VI, Refunding RB
Series A-2-B, 5.00%, 06/01/45		4,010		4,281,004
Series A-2-B, 5.00%, 06/01/51		4,865		5,179,084

S C H E D U L E    O F   I N V E S T M E N T S 8

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
New York (continued)
New York Liberty Development Corp., Refunding RB
Series 1, Class 1, 5.00%, 11/15/44(b)	$	15,115	$	15,910,170
Series 2, Class 2, 5.15%, 11/15/34(b)		450		485,020
Series 2, Class 2, 5.38%, 11/15/40(b)		1,070		1,141,097
Series A, 2.88%, 11/15/46		14,320		12,051,640
Series-A, 3.00%, 11/15/51		4,025		3,458,022
New York State Dormitory Authority, Refunding RB
5.00%, 12/01/33(b)		590		661,104
5.00%, 12/01/35(b)		785		875,665
Series A, 4.00%, 03/15/49		32,925		34,555,281
New York State Housing Finance Agency, RB, M/F Housing
Series J-1, (SONYMA), 2.45%, 11/01/41		2,950		2,481,269
Series J-1, (SONYMA), 2.65%, 11/01/46		3,935		3,239,186
New York Transportation Development Corp., ARB, Series A, AMT, 5.25%, 01/01/50		3,000		3,152,211
New York Transportation Development Corp., RB
AMT, 5.00%, 10/01/35		1,295		1,439,971
AMT, 4.00%, 01/01/36		5,000		5,086,080
AMT, 5.00%, 10/01/40		3,650		4,063,074
AMT, 4.00%, 10/31/46		2,220		2,282,378
AMT, 4.00%, 04/30/53		1,145		1,168,421
New York Transportation Development Corp., Refunding ARB, AMT, 5.38%, 08/01/36		3,665		4,198,239
Niagara Area Development Corp., RB, 5.00%, 07/01/52		1,420		1,443,236
Niagara Area Development Corp., Refunding RB, Series A, AMT, 4.75%, 11/01/42(b)		530		537,317
State of New York Mortgage Agency, RB, S/F Housing, Series 239, (SONYMA), 2.60%, 10/01/44		4,040		3,444,585
Triborough Bridge & Tunnel Authority, RB, Series A, 4.00%, 11/15/54		670		695,500
Westchester County Healthcare Corp., RB, Series A, Senior Lien, 5.00%, 11/01/44		1,290		1,346,355
Westchester County Local Development Corp., Refunding RB
5.00%, 07/01/46(b)		530		533,441
5.00%, 07/01/56(b)		5,000		4,903,350
Series A, 5.13%, 07/01/55		1,100		1,049,028
Westchester Tobacco Asset Securitization Corp., Refunding RB
Sub-Series C, 4.00%, 06/01/42		850		886,452
Sub-Series C, 5.13%, 06/01/51		2,000		2,176,070
				152,237,730
North Carolina — 0.1%
North Carolina Turnpike Authority, RB, Senior Lien, 4.00%, 01/01/55		3,000		3,082,065
North Dakota — 0.4%
County of Cass North Dakota, Refunding RB, Series B, 5.25%, 02/15/58		1,785		1,944,441
North Dakota Housing Finance Agency, RB, M/F Housing, Series A, 4.00%, 01/01/53(d)		2,070		2,180,145
University of North Dakota, COP, Series A, (AGM), 2.50%, 06/01/54		6,200		4,766,808
				8,891,394
Ohio — 2.2%
American Municipal Power Inc., Refunding RB 4.00%, 02/15/36		250		269,056

Security	Par (000)		Value
Ohio (continued)
American Municipal Power Inc., Refunding RB (continued)
4.00%, 02/15/37	$	3,500	$	3,766,906
4.00%, 02/15/38		3,825		4,110,980
Buckeye Tobacco Settlement Financing Authority, Refunding RB, Series B-2, Class 2, 5.00%, 06/01/55		5,490		5,682,918
Cleveland-Cuyahoga County Port Authority, RB
4.00%, 07/01/46		190		199,423
4.00%, 07/01/51		260		272,841
Cleveland-Cuyahoga County Port Authority, Refunding TA(b)
4.00%, 12/01/55		940		844,292
4.50%, 12/01/55		1,230		1,068,037
County of Hamilton Ohio, Refunding RB, Series C, 5.00%, 01/01/46		1,435		1,491,533
County of Hardin Ohio, Refunding RB
5.00%, 05/01/30		620		640,340
5.25%, 05/01/40		1,235		1,253,862
5.50%, 05/01/50		2,895		2,939,091
Franklin County Convention Facilities Authority, RB
5.00%, 12/01/44		1,800		1,884,753
5.00%, 12/01/51		4,000		4,164,448
Hickory Chase Community Authority, Refunding RB, 5.00%, 12/01/40(b)		1,865		1,856,227
Jefferson County Port Authority, RB, AMT, 3.50%, 12/01/51(b)		4,125		3,394,669
Ohio Air Quality Development Authority, RB, AMT, 5.00%, 07/01/49(b)		5,000		5,208,120
Port of Greater Cincinnati Development Authority, RB, 4.25%, 12/01/50(b)		1,100		911,192
Southern Ohio Port Authority, RB, Series A, AMT, 7.00%, 12/01/42(b)		5,980		5,845,265
				45,803,953
Oklahoma — 1.6%
Norman Regional Hospital Authority, RB, 4.00%, 09/01/45		3,565		3,632,282
Oklahoma Development Finance Authority, RB 7.25%, 09/01/51(b)		14,390		16,129,190
Series A-2, 7.25%, 09/01/51(b)		1,920		2,152,053
Series B, 5.00%, 08/15/38		4,585		4,869,206
Series B, 5.25%, 08/15/43		4,130		4,415,338
Tulsa Authority for Economic Opportunity, TA, 4.38%, 12/01/41(b)		1,180		1,048,586
Tulsa County Industrial Authority, Refunding RB, 5.25%, 11/15/37		1,050		1,123,595
				33,370,250
Oregon — 0.4%
Medford Hospital Facilities Authority, Refunding RB
Series A, 4.00%, 08/15/50		4,845		5,119,992
Series A, 5.00%, 08/15/50		2,000		2,286,218
Oregon State Facilities Authority, RB(b)
Series A, 5.00%, 06/15/49		915		913,303
Series A, 5.25%, 06/15/55		505		509,911
				8,829,424
Pennsylvania — 1.2%
Allentown Neighborhood Improvement Zone Development Authority, Refunding RB Series A, 5.00%, 05/01/35		1,185		1,187,964

9

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Pennsylvania (continued)
Allentown Neighborhood Improvement Zone Development Authority, Refunding RB (continued)
Series A, 5.00%, 05/01/42	$	2,730	$	2,736,817
Bucks County Industrial Development Authority, RB
4.00%, 07/01/46		275		282,170
4.00%, 07/01/51		200		205,237
City of Philadelphia Water & Wastewater Revenue, RB, Series A, 5.00%, 11/01/50		6,000		6,944,094
East Hempfield Township Industrial Development Authority, RB, 5.00%, 07/01/24(c)		2,750		2,933,408
Montgomery County Higher Education and Health Authority, Refunding RB, Series A, 4.00%, 09/01/49		880		896,412
Montgomery County Industrial Development Authority, Refunding RB, 5.00%, 12/01/46		1,470		1,551,037
Northampton County Industrial Development Authority, TA, 7.00%, 07/01/32		1,050		1,087,170
Pennsylvania Economic Development Financing Authority, RB, AMT, 5.00%, 06/30/42		895		954,351
Pennsylvania Economic Development Financing Authority, Refunding RB, AMT, 5.50%, 11/01/44		5,390		5,559,904
				24,338,564
Puerto Rico — 10.8%
Children’s Trust Fund, RB, Series A, 0.00%, 05/15/57(e)		135,505		8,292,906
Children’s Trust Fund, Refunding RB, Series B, 0.00%, 05/15/55(e)		2,000		189,696
Commonwealth of Puerto Rico(a)
0.00%, 11/01/43		15,622		8,396,770
1.00%, 11/01/51		13,416		6,476,143
Commonwealth of Puerto Rico, GO
Series A1, Restructured, 5.25%, 07/01/23		2,065		2,116,130
Series A1, Restructured, 5.38%, 07/01/25		2,059		2,175,488
Series A1, Restructured, 5.63%, 07/01/27		2,040		2,229,373
Series A1, Restructured, 5.63%, 07/01/29		3,622		4,018,713
Series A1, Restructured, 5.75%, 07/01/31		1,950		2,221,438
Series A1, Restructured, 4.00%, 07/01/33		1,849		1,808,219
Series A1, Restructured, 4.00%, 07/01/35		1,662		1,606,669
Series A1, Restructured, 4.00%, 07/01/37		1,426		1,372,182
Series A1, Restructured, 4.00%, 07/01/41		1,939		1,840,831
Series A1, Restructured, 4.00%, 07/01/46		2,017		1,898,575
Commonwealth of Puerto Rico, GO, CAB(e)
Series A, Restructured, 0.00%, 07/01/24		951		866,902
Series A, Restructured, 0.00%, 07/01/33		2,379		1,374,347
Puerto Rico Commonwealth Aqueduct & Sewer Authority Refunding RB(d)
Series A, 5.00%, 07/01/22		—		—
Series A, 5.00%, 07/01/24		—		—
Series A, 5.00%, 07/01/25		—		—
Series A, 5.00%, 07/01/28		—		—
Series A, 5.00%, 07/01/29		—		—
Series A, 5.00%, 07/01/33		—		—
Series A, 5.00%, 07/01/37		—		—
Series A, 4.00%, 07/01/42		—		—
Series A, 4.00%, 07/01/47		—		—
Puerto Rico Commonwealth Aqueduct & Sewer Authority, Refunding RB(b)
Series B, 5.00%, 07/01/37		1,365		1,569,603
Series A, Senior Lien, 5.00%, 07/01/35		4,890		5,552,590

Security	Par (000)		Value
Puerto Rico (continued)
Puerto Rico Commonwealth Aqueduct & Sewer Authority, Refunding RB(b) (continued)
Series A, Senior Lien, 5.00%, 07/01/47	$	8,605	$	9,555,242
Puerto Rico Electric Power Authority, RB 0.00%, 01/01/23		4,430		4,341,334
3rd Series, 5.40%, 01/01/23		208		203,523
Series A, 7.25%, 07/01/30(g)(h)		250		245,000
Series A, 7.00%, 07/01/33(g)(h)		8,735		8,560,300
Series A, 6.75%, 07/01/36(g)(h)		5,830		5,713,400
Series A, 7.00%, 07/01/40(g)(h)		1,000		980,000
Series A, 5.00%, 07/01/42(g)(h)		2,315		2,266,762
Series A, 5.05%, 07/01/42(g)(h)		1,080		1,057,496
Series A, 7.00%, 07/01/43(g)(h)		775		759,500
Series A-1, 10.00%, 07/01/19(g)(h)		230		249,780
Series A-2, 10.00%, 07/01/19(g)(h)		1,161		1,260,149
Series A-3, 10.00%, 07/01/19(g)(h)		748		811,220
Series B-3, 10.00%, 07/01/19(g)(h)		748		811,220
Series C-1, 5.40%, 01/01/18(g)(h)		2,054		2,013,093
Series C-2, 5.40%, 07/01/18(g)(h)		2,054		2,013,418
Series C-4, 5.40%, 07/01/20(g)(h)		208		203,524
Series CCC, 5.00%, 07/01/22(g)(h)		715		700,102
Series CCC, 5.00%, 07/01/25(g)(h)		620		607,081
Series CCC, 5.25%, 07/01/26(g)(h)		590		577,706
Series CCC, 5.25%, 07/01/28(g)(h)		1,945		1,810,382
Series D-1, 7.50%, 01/01/20(g)(h)		2,332		2,285,585
Series TT, 5.00%, 07/01/18(g)(h)		900		881,247
Series TT, 5.00%, 07/01/25(g)(h)		3,270		3,201,863
Series TT, 5.00%, 07/01/26(g)(h)		455		445,519
Series WW, 5.50%, 07/01/17(g)(h)		475		465,102
Series WW, 5.50%, 07/01/18(g)(h)		415		406,353
Series WW, 5.50%, 07/01/19(g)(h)		335		328,020
Series WW, 5.38%, 07/01/22(g)(h)		4,500		4,406,234
Series WW, 5.38%, 07/01/24(g)(h)		815		798,018
Series WW, 5.25%, 07/01/25(g)(h)		1,940		1,899,576
Series WW, 5.25%, 07/01/33(g)(h)		315		308,436
Series WW, 5.50%, 07/01/38(g)(h)		415		406,353
Series XX, 5.25%, 07/01/27(g)(h)		230		225,208
Series XX, 5.25%, 07/01/35(g)(h)		705		690,310
Series XX, 5.75%, 07/01/36(g)(h)		2,870		2,810,198
Series XX, 5.25%, 07/01/40(g)(h)		8,385		8,210,282
Puerto Rico Electric Power Authority, Refunding RB(g)(h)
Series AAA, 5.25%, 07/01/22		765		749,060
Series AAA, 5.25%, 07/01/25		3,560		3,376,488
Series AAA, 5.25%, 07/01/28		3,655		3,461,595
Series AAA, 5.25%, 07/01/29		190		186,041
Series UU, 1.16%, 07/01/17(a)		2,660		2,318,400
Series UU, 1.00%, 07/01/18(a)		125		112,500
Series UU, 0.00%, 07/01/20(a)		1,135		1,021,500
Series UU, 1.35%, 07/01/31(a)		1,345		1,210,500
Series ZZ, 5.00%, 07/01/17		330		323,124
Series ZZ, 5.25%, 07/01/19		1,050		1,028,121
Series ZZ, 5.25%, 07/01/23		370		340,600
Series ZZ, 5.25%, 07/01/24		5,050		4,690,056
Series ZZ, 5.25%, 07/01/25		265		259,478
Series ZZ, 5.00%, 07/01/28		345		337,811
Puerto Rico Infrastructure Financing Authority, Refunding RB, Series C, (FGIC), 5.50%, 07/01/21(g)(h)		1,662		1,625,880

S C H E D U L E    O F   I N V E S T M E N T S 10

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Puerto Rico (continued)
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB
Series A-1, Restructured, 4.75%, 07/01/53	$	15,177	$	16,081,929
Series A-1, Restructured, 5.00%, 07/01/58		17,813		18,904,224
Series A-2, Restructured, 4.33%, 07/01/40		15,872		16,392,319
Series A-2, Restructured, 4.54%, 07/01/53		1,564		1,631,341
Series A-2, Restructured, 4.78%, 07/01/58		8,434		8,881,407
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB, CAB(e)
Series A-1, Restructured, 0.00%, 07/01/24		7,329		6,870,114
Series A-1, Restructured, 0.00%, 07/01/29		2,914		2,374,604
Series A-1, Restructured, 0.00%, 07/01/31		1,895		1,432,739
Series A-1, Restructured, 0.00%, 07/01/33		679		475,371
Series A-1, Restructured, 0.00%, 07/01/46		4,890		1,498,032
Series A-1, Restructured, 0.00%, 07/01/51		12,936		2,870,007
Series B-1, Restructured, 0.00%, 07/01/46		2,066		633,177
				225,601,529
Rhode Island — 0.9%
Tobacco Settlement Financing Corp., Refunding RB
Series A, 5.00%, 06/01/35		1,005		1,071,527
Series A, 5.00%, 06/01/40		5,500		5,824,907
Series B, 4.50%, 06/01/45		6,350		6,580,981
Series B, 5.00%, 06/01/50		5,650		6,003,865
				19,481,280
South Carolina — 0.7%
City of Hardeeville SC, SAB(b)
3.00%, 05/01/27		500		486,325
3.50%, 05/01/32		850		797,669
3.88%, 05/01/41		1,400		1,283,540
4.00%, 05/01/52		1,350		1,172,621
County of Dorchester South Carolina, SAB, 6.00%, 10/01/51(b)		2,240		2,346,505
South Carolina Jobs-Economic Development Authority, RB
Series A, 5.00%, 11/15/42		585		612,459
Series A, 5.00%, 11/15/54		280		286,324
South Carolina Jobs-Economic Development Authority, Refunding RB
4.00%, 11/15/27		575		584,844
5.25%, 11/15/52		800		823,598
Series A, 5.00%, 05/01/48		5,825		6,375,521
				14,769,406
South Dakota — 0.7%
South Dakota Housing Development Authority, Refunding RB, S/F Housing
3.00%, 11/01/52		7,820		7,833,122
Series A, Class A, (FHLMC, FNMA, GNMA), 3.00%, 11/01/51		6,265		6,275,306
				14,108,428
Tennessee — 1.4%
Chattanooga Health Educational & Housing Facility Board, Refunding RB, Series A, 4.00%, 08/01/44		410		416,346
Franklin Health & Educational Facilities Board, Refunding RB, Series A, 7.50%, 06/01/47(b)(g)(h)		4,060		1,219,795
Knox County Health Educational & Housing Facility Board, Refunding RB, 5.00%, 04/01/36		560		612,705
Memphis-Shelby County Industrial Development Board, Refunding TA Series A, 5.50%, 07/01/37		1,650		1,434,810

Security	Par (000)		Value
Tennessee (continued)
Memphis-Shelby County Industrial Development Board, Refunding TA (continued)
Series A, 5.63%, 01/01/46	$	1,875	$	1,550,329
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board, RB, Series A, 5.00%, 07/01/40		925		995,877
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board, Refunding RB
Series A, 4.00%, 10/01/49		1,635		1,627,544
Series A, 5.25%, 10/01/58		7,565		8,242,491
Metropolitan Government Nashville & Davidson County Industrial Development Board, SAB, 4.00%, 06/01/51(b)		2,350		2,047,522
Metropolitan Government Nashville & Davidson County Industrial Development Board, SAB, CAB, 0.00%, 06/01/43(b)(e)		4,000		1,389,736
Nashville Metropolitan Development & Housing Agency, TA, 5.13%, 06/01/36(b)		500		540,768
Tennergy Corp., RB, Series A, 4.00%, 12/01/51(a)		9,000		9,549,594
				29,627,517
Texas — 4.3%
Angelina & Neches River Authority, RB, Series A, AMT, 7.50%, 12/01/45(b)		2,340		2,107,605
Arlington Higher Education Finance Corp., RB 5.00%, 06/15/51		2,045		2,061,137
(PSF-GTD), 5.00%, 08/15/52(d)		3,440		3,932,980
5.63%, 08/15/54(b)		6,260		6,342,344
Series A, 5.88%, 03/01/24		230		237,618
Arlington Higher Education Finance Corp., Refunding RB, 5.00%, 08/15/51		1,000		1,017,141
Brazoria County Industrial Development Corp., RB, AMT, 7.00%, 03/01/39		1,610		1,722,669
Central Texas Regional Mobility Authority, Refunding RB, 0.00%, 01/01/31(e)		4,000		3,074,424
Central Texas Regional Mobility Authority, Refunding RB, CAB(e)
0.00%, 01/01/28		3,000		2,561,928
0.00%, 01/01/29		500		413,166
0.00%, 01/01/30		1,330		1,060,317
City of Crandall, SAB(b)
3.38%, 09/15/26		100		97,774
4.00%, 09/15/31		200		196,358
4.75%, 09/15/31		100		97,612
4.25%, 09/15/41		770		739,497
5.00%, 09/15/41		500		481,378
City of Houston Texas Airport System Revenue, RB AMT, 5.00%, 07/15/28		2,725		3,064,748
Series A, AMT, 6.63%, 07/15/38		1,110		1,113,098
City of Houston Texas Airport System Revenue, Refunding ARB, AMT, 5.00%, 07/15/27		615		670,426
City of Houston Texas Airport System Revenue, Refunding RB, Series C, AMT, 5.00%, 07/15/27		3,925		4,276,060
City of Marble Falls, SAB(b)
4.63%, 09/01/31		100		94,982
4.88%, 09/01/41		295		262,893
5.13%, 09/01/51		500		434,422
City of San Marcos TX, SAB(b)
3.75%, 09/01/27		228		221,443
4.25%, 09/01/42		750		661,530

11

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Texas (continued)
City of San Marcos, SAB(b)
4.00%, 09/01/32	$	237	$	223,874
4.50%, 09/01/51		520		450,980
Fort Bend County Industrial Development Corp., RB, Series B, 4.75%, 11/01/42		3,380		3,414,131
Harris County Cultural Education Facilities Finance Corp., Refunding RB
Series A, 5.00%, 01/01/38		510		516,167
Series A, 5.00%, 01/01/43		520		524,417
Series A, 5.13%, 01/01/48		1,535		1,548,448
Harris County-Houston Sports Authority, Refunding RB, Series G, Senior Lien, (NPFGC), 0.00%, 11/15/41(e)		350		131,386
Hemphill County Hospital District, GOL
4.63%, 02/01/39		1,500		1,491,041
4.75%, 02/01/45		2,500		2,436,950
Hidalgo County Regional Mobility Authority, RB
Series A, 4.00%, 12/01/39		745		776,306
Series A, 4.00%, 12/01/40		745		774,199
Series A, 4.00%, 12/01/41		745		772,730
Hidalgo County Regional Mobility Authority, Refunding RB
Series B, 4.00%, 12/01/38		585		581,771
Series B, Junior Lien, 4.00%, 12/01/39		1,000		985,183
Series B, Junior Lien, 4.00%, 12/01/40		1,040		1,012,964
Series B, Junior Lien, 4.00%, 12/01/41		1,000		964,940
Houston Higher Education Finance Corp., RB, 4.00%, 10/01/51		1,400		1,424,751
Mission Economic Development Corp., Refunding RB, AMT, Senior Lien, 4.63%, 10/01/31(b)		1,385		1,453,844
New Hope Cultural Education Facilities Finance Corp., RB
Series A, 5.88%, 04/01/23(c)		890		926,583
Series A, 6.00%, 04/01/23(c)		1,355		1,412,369
Series A, 0.00%, 12/01/25(b)(e)		3,165		3,099,624
Series A, 5.00%, 07/01/57		3,000		3,207,717
New Hope Higher Education Finance Corp., RB, Series A, 5.75%, 06/15/51(b)		5,580		4,859,711
Newark Higher Education Finance Corp., RB(b)
Series A, 5.50%, 08/15/35		375		400,189
Series A, 5.75%, 08/15/45		735		784,825
San Antonio Education Facilities Corp., RB
Series A, 5.00%, 10/01/41		645		644,458
Series A, 5.00%, 10/01/51		885		859,922
Tarrant County Cultural Education Facilities Finance Corp., RB, Series B, 5.00%, 07/01/48		8,560		9,628,759
Texas Transportation Commission, RB, CAB(e)
0.00%, 08/01/46		2,580		846,108
0.00%, 08/01/47		3,850		1,200,819
0.00%, 08/01/48		4,070		1,206,210
0.00%, 08/01/49		3,825		1,077,288
0.00%, 08/01/50		5,485		1,460,568
0.00%, 08/01/51		3,230		813,805
0.00%, 08/01/52		3,230		769,328
0.00%, 08/01/53		290		65,378
				89,691,293

Security	Par (000)		Value
Utah(b) — 0.1%
Utah Charter School Finance Authority, RB
Series A, 5.00%, 06/15/41	$	590	$	619,427
Series A, 5.00%, 06/15/52		750		774,766
				1,394,193
Vermont — 0.5%
East Central Vermont Telecommunications District, RB(b)
Series A, 4.75%, 12/01/40		2,850		2,765,726
Series A, 4.50%, 12/01/44		3,695		3,363,481
Series A, 4.50%, 12/01/50		3,000		2,629,977
Vermont Student Assistance Corp., RB, Class A, AMT, 2.38%, 06/15/39		3,015		2,547,355
				11,306,539
Virginia — 0.7%
Hanover County Economic Development Authority, RB, 4.00%, 07/01/40(b)(d)		1,790		1,726,555
Hanover County Economic Development Authority, Refunding RB, Series A, 5.00%, 07/01/47		1,015		1,016,163
Henrico County Economic Development Authority, Refunding RB, 4.00%, 10/01/50		1,250		1,302,238
Lower Magnolia Green Community Development Authority, SAB(b)
5.00%, 03/01/35		490		502,996
5.00%, 03/01/45		505		513,931
Lynchburg Economic Development Authority, Refunding RB, 4.00%, 01/01/55		670		678,771
Norfolk Redevelopment & Housing Authority, RB, Series A, 5.00%, 01/01/49		1,250		1,300,314
Salem Economic Development Authority, Refunding RB, 4.00%, 04/01/45		830		852,812
Virginia Beach Development Authority, Refunding RB, 4.00%, 09/01/48		2,885		2,900,112
Virginia Small Business Financing Authority, Refunding RB, AMT, Senior Lien, 6.00%, 01/01/37		3,360		3,392,605
				14,186,497
Washington — 2.7%
Greater Wenatchee Regional Events Center Public Facilities District, Refunding RB, Series A, 5.50%, 09/01/22(c)		1,005		1,022,964
Port of Seattle Washington, Refunding ARB, Series C, AMT, Intermediate Lien, 5.00%, 08/01/46		11,915		13,456,777
Washington Economic Development Finance Authority, RB, AMT, 5.63%, 12/01/40(b)		3,470		3,888,975
Washington Health Care Facilities Authority, Refunding RB, Series A, 4.00%, 08/01/44		885		902,746
Washington State Convention Center Public Facilities District, RB
4.00%, 07/01/31		3,750		3,830,134
3.00%, 07/01/58		5,365		3,893,804
Washington State Housing Finance Commission, RB(b)
Series A, 5.00%, 07/01/50		620		656,305
Series A, 5.00%, 07/01/56		700		735,731
Washington State Housing Finance Commission, RB, M/F Housing, Series A-1, 3.50%, 12/20/35		23,816		23,439,652

S C H E D U L E    O F   I N V E S T M E N T S 12

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Washington (continued)
Washington State Housing Finance Commission, Refunding RB(b)
5.75%, 01/01/35	$	355	$	371,535
6.00%, 01/01/45		940		979,800
5.00%, 01/01/48		2,410		2,606,463
				55,784,886
Wisconsin — 3.9%
Public Finance Authority, ARB
AMT, 4.00%, 07/01/41		530		490,712
AMT, 4.25%, 07/01/54		3,690		3,310,793
Public Finance Authority, RB
4.25%, 06/15/31(b)		170		161,666
5.00%, 06/15/39		310		340,419
5.00%, 06/15/41(b)		1,435		1,383,883
5.00%, 01/01/42(b)		1,555		1,585,688
5.00%, 12/01/45(b)		280		294,764
6.85%, 11/01/46(b)		1,325		1,349,043
7.00%, 11/01/46(b)		805		824,333
5.00%, 06/15/49		955		1,035,648
5.63%, 06/15/49(b)		6,000		5,887,476
5.00%, 04/01/50(b)		315		328,452
5.00%, 06/15/51(b)		1,060		965,695
5.25%, 12/01/51(b)		5,280		4,292,439
5.00%, 06/15/53		645		697,669
5.00%, 06/15/55(b)		2,405		2,211,592
5.00%, 01/01/56(b)		3,790		3,820,597
4.75%, 06/15/56(b)		2,415		2,026,050
Series A, 6.25%, 10/01/31(b)		910		917,058
Series A, 5.00%, 06/01/40(b)		750		761,057
Series A, 5.38%, 06/01/44(b)		1,215		1,131,192
Series A, 5.38%, 07/15/47(b)		1,595		1,707,676
Series A, 7.00%, 10/01/47(b)		910		918,893
Series A, 5.00%, 06/01/49(b)		1,340		1,341,786
Series A, 5.63%, 06/15/49(b)		8,105		8,243,855
Series A, 5.50%, 06/01/54(b)		1,500		1,374,104
Series A, 5.00%, 06/15/55(b)		11,540		10,562,597
Series A-1, 4.50%, 01/01/35(b)		895		860,999
Series A-1, 5.50%, 12/01/48(b)(g)(h)		38		12,653
Series A-1, 5.00%, 01/01/55(b)		2,470		2,424,063
Series B, 0.00%, 01/01/35(b)(e)		1,185		463,952
Series B, 0.00%, 01/01/60(b)(e)		31,635		1,838,848
AMT, 4.00%, 09/30/51		3,370		3,359,647
AMT, 4.00%, 03/31/56		3,540		3,466,927
Public Finance Authority, Refunding RB
4.00%, 04/01/32(b)		595		610,337
4.00%, 12/01/41		1,500		1,521,309
4.00%, 04/01/42(b)		650		626,029
5.00%, 03/01/52(b)		1,300		1,348,084
4.00%, 04/01/52(b)		815		770,673
Series A, 5.00%, 10/01/34(b)		280		301,440
Series A, 5.00%, 10/01/39(b)		680		727,521

Security	Par (000)		Value
Wisconsin (continued)
Wisconsin Health & Educational Facilities Authority, Refunding RB
5.00%, 11/01/46	$	130	$	138,873
4.00%, 01/01/47		3,900		3,565,555
4.00%, 01/01/57		1,050		912,667
Wisconsin Housing & Economic Development Authority, RB, M/F Housing, Series A, 4.70%, 07/01/47		740		778,205
				81,692,919
Total Municipal Bonds — 90.9% (Cost: $1,926,696,190)				1,898,863,756
Municipal Bonds Transferred to Tender Option Bond Trusts(i)
California — 0.7%
California Health Facilities Financing Authority, Refunding RB, 4.00%, 08/15/48		5,767		6,187,779
San Diego County Regional Airport Authority, ARB(j)
Series B, AMT, Subordinate, 4.00%, 07/01/56		2,507		2,609,720
Series B, AMT, Subordinate, 5.00%, 07/01/56		5,551		6,155,013
				14,952,512
Georgia — 0.2%
Dalton Whitfield County Joint Development Authority, RB, 4.00%, 08/15/48		3,140		3,235,311
Illinois — 0.6%
Illinois Finance Authority, Refunding RB, Series C, 4.00%, 02/15/41		6,510		6,707,943
Illinois State Toll Highway Authority, RB, Series A, 5.00%, 01/01/40		5,011		5,360,374
				12,068,317
Maryland — 0.7%
Maryland Health & Higher Educational Facilities Authority, RB, Series B, 4.00%, 04/15/50		15,000		15,720,845
Massachusetts — 0.2%
Commonwealth of Massachusetts Transportation Fund Revenue, RB, Series A, 4.00%, 06/01/45		3,463		3,560,344
New Jersey — 1.3%
New Jersey Health Care Facilities Financing Authority, RB, 4.00%, 07/01/51		26,610		27,818,830
New York — 4.4%
New York City Housing Development Corp., RB, M/F Housing
Series C-1A, 4.15%, 11/01/39		3,107		3,123,579
Series C-1A, 4.20%, 11/01/44		5,695		5,725,411
Series C-1A, 4.30%, 11/01/47		4,660		4,685,301
New York Power Authority, Refunding RB, Series A, 4.00%, 11/15/60		3,421		3,613,077
New York State Dormitory Authority, Refunding RB
Series D, 4.00%, 02/15/47		17,080		17,724,949
Series E, 5.00%, 03/15/36		21,670		23,495,990

13

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund (Percentages shown are based on Net Assets)

Security	Par (000)		Value
New York (continued)
New York State Urban Development Corp., RB, Series A, 4.00%, 03/15/46	$	13,005	$	13,646,042
Port Authority of New York & New Jersey, ARB, Series 221, AMT, 4.00%, 07/15/60		16,595		16,912,277
Port Authority of New York & New Jersey, Refunding ARB, 194th Series, 5.25%, 10/15/55		2,925		3,140,204
				92,066,830
North Carolina — 0.2%
North Carolina Capital Facilities Finance Agency, Refunding RB, Series B, 5.00%, 10/01/55		2,930		3,217,604
Ohio — 0.5%
Ohio State University, RB, 4.00%, 12/01/48		8,790		9,489,253
Pennsylvania — 0.7%
Pennsylvania Economic Development Financing Authority, RB, Series A-1, 4.00%, 04/15/50		11,000		11,369,244
Pennsylvania Turnpike Commission, RB, Sub- Series A, 5.50%, 12/01/42		3,677		4,095,508
				15,464,752
Rhode Island — 0.1%
Narragansett Bay Commission, Refunding RB, Series A, 4.00%, 09/01/43		2,641		2,675,718
Texas — 0.2%
Lower Colorado River Authority, Refunding, RB, 4.00%, 05/15/43		3,480		3,490,195
Virginia — 0.3%
Hampton Roads Transportation Accountability Commission, RB, Series A, Senior Lien, 4.00%, 07/01/60(j)		6,249		6,638,855
Washington — 0.4%
Snohomish County Public Utility District No.1, RB, 5.00%, 12/01/45		8,664		9,422,032
Wisconsin — 0.1%
Wisconsin Health & Educational Facilities Authority, Refunding RB, 4.00%, 12/01/46		1,773		1,826,651
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 10.6% (Cost: $227,165,686)				221,648,049
Total Long-Term Investments — 101.5% (Cost: $2,154,674,819)				2,120,539,705

Security	Shares		Value
Short-Term Securities
Money Market Funds — 5.6%
BlackRock Liquidity Funds, MuniCash, Institutional Class, 0.26%(k)(l)		116,210,036	$	116,198,415
Total Short-Term Securities — 5.6% (Cost: $116,206,634)				116,198,415
Total Investments — 107.1% (Cost: $2,270,881,453)				2,236,738,120
Liabilities in Excess of Other Assets — (0.5)%				(9,510,774	)
Liability for TOB Trust Certificates, Including Interest Expense and Fees Payable — (6.6)%				(138,289,853	)
Net Assets — 100.0%			$	2,088,937,493

^(a)  Variable rate security. Interest rate resets periodically. The rate shown is the effective interest rate as of period end. Security description also includes the reference rate and spread if published and available.

^(b)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(c)  U.S. Government securities held in escrow, are used to pay interest on this security as well as to retire the bond in full at the date indicated, typically at a premium to par.

^(d)  When-issued security.

^(e)  Zero-coupon bond.

^(f)  Step coupon security. Coupon rate will either increase (step-up bond) or decrease (step-down bond) at regular intervals until maturity. Interest rate shown reflects the rate currently in effect.

^(g)  Issuer filed for bankruptcy and/or is in default.

^(h)  Non-income producing security.

⁽ⁱ⁾  Represent bonds transferred to a TOB Trust in exchange of cash and residual certificates received by the Fund. These bonds serve as collateral in a secured borrowing.

^(j)  All or a portion of the security is subject to a recourse agreement. The aggregate maximum potential amount the Fund could ultimately be required to pay under the agreements, which expire between July 1, 2028 to July 1, 2029, is $9,859,384.

^(k)  Affiliate of the Fund.

^(l)  Annualized 7-day yield as of period end.

Affiliates

Investments in issuers considered to be affiliate(s) of the Fund during the period ended March 31, 2022 for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliated Issuer	Value at 06/30/21		Purchases at Cost		Proceeds from Sales			Net Realized Gain (Loss)			Change in Unrealized Appreciation (Depreciation)			Value at 03/31/22		Shares Held at 03/31/22		Income		Capital Gain Distributions from Underlying Funds
BlackRock Liquidity Funds, MuniCash, Institutional Class	$	156,292,907	$	—	$	(40,048,858	)(a)	$	(36,995	)	$	(8,639	)	$	116,198,415		116,210,036	$	26,996	$	—

^(a)  Represents net amount purchased (sold).

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Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Short Contracts
10-Year U.S. Treasury Note		507		06/21/22	$	62,234	$	1,428,877
U.S. Long Bond		506		06/21/22		75,979		1,643,360
5-Year U.S. Treasury Note		364		06/30/22		41,698		886,934
							$	3,959,171

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three

broad levels for financial reporting purposes as follows:

• Level 1 – Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Fund has the ability to access;

• Level 2 – Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs); and

• Level 3 – Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the BlackRock Global Valuation Methodologies Committee’s (the “Global Valuation Committee’s”) assumptions used in determining the fair value of financial instruments).

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for financial instruments is based on the pricing transparency of the financial instruments and is not necessarily an indication of the risks associated with investing in those securities. For information about the Fund’s policy regarding valuation of financial instruments, refer to its most recent financial statements.

The following table summarizes the Fund’s financial instruments categorized in the fair value hierarchy. The breakdown of the Fund’s financial instruments into major categories is disclosed in the Schedule of Investments above.

	Level 1		Level 2		Level 3		Total
Assets
Investments
Long-Term Investments
Corporate Bonds	$	—	$	27,900	$	—	$	27,900
Municipal Bonds		—		1,898,863,756		—		1,898,863,756
Municipal Bonds Transferred to Tender Option Bond Trusts		—		221,648,049		—		221,648,049
Short-Term Securities
Money Market Funds		116,198,415		—		—		116,198,415
	$	116,198,415	$	2,120,539,705	$	—	$	2,236,738,120
Derivative Financial Instruments(a)
Assets
Interest Rate Contracts	$	3,959,171	$	—	$	—	$	3,959,171

^(a)  Derivative financial instruments are futures contracts. Futures contracts are valued at the unrealized appreciation (depreciation) on the instrument.

The Fund may hold assets and/or liabilities in which the fair value approximates the carrying amount for financial reporting purposes. As of period end, TOB Trust Certificates of $138,216,081 are categorized as Level 2 within the fair value hierarchy.

Portfolio Abbreviation
AGC	Assured Guaranty Corp.
AGM	Assured Guaranty Municipal Corp.

Portfolio Abbreviation (continued)
AMT	Alternative Minimum Tax
ARB	Airport Revenue Bonds

15

Schedule of Investments (unaudited) (continued) March 31, 2022 BlackRock High Yield Municipal Fund

Portfolio Abbreviation (continued)
CAB	Capital Appreciation Bonds
COP	Certificates of Participation
FGIC	Financial Guaranty Insurance Co.
FHA	Federal Housing Administration
FHLMC	Federal Home Loan Mortgage Corp.
FNMA	Federal National Mortgage Association
GNMA	Government National Mortgage Association
GO	General Obligation Bonds
GOL	General Obligation Ltd.
GTD	GTD Guaranteed
M/F	Multi-Family
NPFGC	National Public Finance Guarantee Corp.
PSF-GTD	Permanent School Fund Guaranteed
RB	Revenue Bond
S/F	Single-Family
SAB	Special Assessment Bonds
SONYMA	State of New York Mortgage Agency
ST	Special Tax
TA	Tax Allocation

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