Blackrock Municipal Bond Fund NPORTP BlackRock High Yield Municipal Fund (Mar 2021 report)

Schedule of Investments (unaudited)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Municipal Bonds

Alabama — 1.6%
Chelsea Park Cooperative District, SAB, 5.00%, 05/01/48	$	945	$	968,833
County of Jefferson Alabama Sewer Revenue, Refunding RB
Series A, Senior Lien, (AGM), 5.00%, 10/01/44		365		405,734
Series D, Sub Lien, 7.00%, 10/01/51		2,355		2,762,580
Series D, Sub-Lien, 6.50%, 10/01/53		3,465		4,014,202
Hoover Industrial Development Board, RB, AMT, 6.38%, 11/01/50^(a)		7,155		8,888,943
Tuscaloosa County Industrial Development Authority, Refunding RB^(b)
Series A, 4.50%, 05/01/32		1,250		1,380,575
Series A, 5.25%, 05/01/44		7,330		8,329,959


				26,750,826

Arizona — 2.8%
Arizona Industrial Development Authority, RB^(b)
5.00%, 07/01/45		1,135		1,211,908
7.10%, 01/01/55		4,760		4,698,263
5.00%, 07/01/55		1,215		1,274,523
Series A, 5.00%, 07/01/39		1,270		1,335,202
Series A, 5.00%, 12/15/39		150		168,773
Series A, 5.00%, 07/01/49		2,790		2,893,425
Series A, 5.00%, 07/15/49		675		740,731
Series A, 5.00%, 12/15/49		345		380,145
Series A, 5.00%, 07/01/54		1,110		1,146,641
Series B, 5.13%, 07/01/47		420		466,032
Series B, 5.25%, 07/01/51		570		632,592
Arizona Industrial Development Authority, Refunding RB^(b)
Series A, 5.00%, 07/01/26		760		837,915
Series A, 5.25%, 07/01/47		3,235		3,535,370
Series A, 5.50%, 07/01/52		2,970		3,191,027
Florence Town, Inc. Industrial Development Authority, RB, 6.00%, 07/01/43		1,375		1,461,020
Glendale Industrial Development Authority, RB
5.00%, 05/15/41		275		302,811
5.00%, 05/15/56		1,090		1,186,596
Industrial Development Authority of the City of Phoenix, RB
5.00%, 07/01/54		1,330		1,499,109
5.00%, 07/01/59		655		736,541
Series A, 5.00%, 07/01/34^(b)		250		257,400
Series A, 6.50%, 07/01/34^(b)		465		535,261
Series A, 5.00%, 07/01/36^(b)		1,225		1,357,827
Series A, 5.00%, 07/01/39^(b)		205		210,400
Series A, 5.00%, 07/01/41^(b)		1,685		1,848,799
Series A, 5.00%, 07/01/43		1,445		1,472,787
Series A, 6.75%, 07/01/44^(b)		810		943,942
Series A, 5.25%, 07/01/48^(b)		1,690		1,730,712
Series A, 5.00%, 07/01/49^(b)		320		326,634
Series A, 5.00%, 07/01/54^(b)		530		540,139
Industrial Development Authority of the City of Phoenix, Refunding RB^(b)
5.00%, 07/01/35		615		670,303
5.00%, 07/01/45		1,500		1,604,880
Series A, 5.00%, 07/01/35		295		321,349


Security	Par (000)		Value


Arizona (continued)
Industrial Development Authority of the County of Pima, RB
5.13%, 07/01/39	$	700	$	709,394
5.25%, 07/01/49		870		877,230
Industrial Development Authority of the County of Pima, Refunding RB, 5.00%, 07/01/56^(b)		1,300		1,315,756
La Paz County Industrial Development Authority, RB, 5.88%, 06/15/48^(b)		1,340		1,400,581
Maricopa County Industrial Development Authority, RB^(b)
5.25%, 10/01/40		1,255		1,297,030
5.50%, 10/01/51		1,255		1,298,285


				46,417,333

Arkansas^(b)— 1.7%
Arkansas Development Finance Authority, RB
AMT, 4.50%, 09/01/49		17,755		19,312,646
AMT, 4.75%, 09/01/49		8,190		9,104,987


				28,417,633

California — 4.4%
California Community Housing Agency, RB, M/F Housing, 4.00%, 08/01/47^(b)		5,120		5,290,138
California County Tobacco Securitization Agency, Refunding RB, Series A, 5.00%, 06/01/36		1,665		1,679,069
California Housing Finance, RB, M/F Housing, Class A, 3.50%, 11/20/35		5,885		6,711,804
California Municipal Finance Authority, ARB, AMT, Senior Lien, 4.00%, 12/31/47		2,560		2,794,854
California Municipal Finance Authority, RB^(b)
Series A, 5.50%, 08/01/34		310		330,758
Series A, 6.00%, 08/01/44		655		698,931
Series A, 6.13%, 08/01/49		570		607,563
California Municipal Finance Authority, Refunding RB
3.00%, 11/01/48		2,000		2,032,420
Series A, 5.00%, 02/01/42		345		401,031
California Public Finance Authority, RB, 6.25%, 07/01/54^(b)		5,270		6,012,543
California School Finance Authority, RB
6.65%, 07/01/33		295		318,311
6.90%, 07/01/43		650		698,698
California Statewide Communities Development Authority, RB^(b)
5.25%, 12/01/38		1,420		1,703,446
5.25%, 12/01/48		1,000		1,166,080
City of San Jose California Hotel Tax Revenue, RB
6.50%, 05/01/36		310		311,370
6.50%, 05/01/42		760		763,268
CMFA Special Finance Agency I, RB, M/F Housing, 4.00%, 04/01/56^(b)		9,450		9,858,524
CSCDA Community Improvement Authority, RB, M/F Housing^(b)
4.00%, 08/01/56		5,000		5,291,750
Series A, 5.00%, 01/01/54		1,050		1,204,077
Golden State Tobacco Securitization Corp., Refunding RB
Series A-1, 3.50%, 06/01/36		5,860		5,964,367
Series A-1, 5.00%, 06/01/47		5,195		5,369,084
Series A-1, 5.25%, 06/01/47		945		979,833
Series A-2, 5.00%, 06/01/47		3,950		4,082,523


S C H E D U L E O F I N V E S T M E N T S		1

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


California (continued)
Hastings Campus Housing Finance Authority, RB, CAB, Sub-Series A, 6.75%, 07/01/61^(b)(c)	$	4,420	$	2,342,158
Riverside County Transportation Commission, RB, Series A, Senior Lien, 5.75%, 06/01/48		2,115		2,329,926
San Francisco City & County Redevelopment Agency Successor Agency, ST, 0.00%, 08/01/43^(d)		3,000		859,320
San Francisco City & County Redevelopment Agency Successor Agency, TA^(b)
Series D, 0.00%, 08/01/23^(d)		1,000		906,870
Sub-Series D, 3.00%, 08/01/21		500		503,675
San Francisco City & County Redevelopment Agency Successor Agency, TA, CAB^(b)(d)
Series D, 0.00%, 08/01/26		580		453,896
Series D, 0.00%, 08/01/31		1,155		704,816


				72,371,103

Colorado — 4.0%
9th Avenue Metropolitan District No. 2, GO, 5.00%, 12/01/48		1,565		1,653,563
Aurora Crossroads Metropolitan District No. 2, GO
Series A, 5.00%, 12/01/40		1,000		1,082,720
Series A, 5.00%, 12/01/50		500		535,650
Aviation Station North Metropolitan District No. 2, GO
Series A, 5.00%, 12/01/39		750		805,830
Series A, 5.00%, 12/01/48		1,350		1,443,285
Brighton Crossing Metropolitan District No. 6, GO, Series A, 5.00%, 12/01/50		500		543,155
Broadway Station Metropolitan District No. 2, GO
Series A, 5.00%, 12/01/35		735		782,033
Series A, 5.13%, 12/01/48		3,925		4,143,897
Bromley Park Metropolitan District No. 2, Refunding GO, Sub-Series B, 6.38%, 12/15/47		937		988,460
Centerra Metropolitan District No. 1, TA, 5.00%, 12/01/47^(b)		820		846,388
Colorado Educational & Cultural Facilities Authority, RB
5.00%, 12/01/33		450		464,751
5.00%, 12/01/42		545		559,094
Colorado Educational & Cultural Facilities Authority, Refunding RB^(b)
5.00%, 12/01/40		115		122,017
5.00%, 12/01/50		155		161,315
5.00%, 12/01/55		180		186,577
Colorado Health Facilities Authority, Refunding RB, Series A, 4.00%, 08/01/44		4,620		5,159,939
Colorado High Performance Transportation Enterprise, RB, 5.00%, 12/31/56		2,500		2,804,100
Constitution Heights Metropolitan District, Refunding GO, 5.00%, 12/01/49		1,260		1,329,766
Copperleaf Metropolitan District No. 3, GO
Series A, 5.00%, 12/01/37		500		525,495
Series A, 5.13%, 12/01/47		1,200		1,258,824
Green Gables Metropolitan District No. 1, Refunding GO, Series A, 5.30%, 12/01/21^(e)		990		1,053,033
Green Valley Ranch East Metropolitan District No. 6, GO, Series A, 5.88%, 12/01/50		2,615		2,798,704
Home Place Metropolitan District, GO, Series A, 5.75%, 12/01/50		2,345		2,481,456
Inspiration Metropolitan District, GO, Series D, 7.50%, 12/15/51		2,487		2,383,889


Security	Par (000)		Value


Colorado (continued)
Jefferson Center Metropolitan District No. 1, RB
Series A-2, 4.13%, 12/01/40	$	580	$	586,270
Series A-2, 4.38%, 12/01/47		1,000		1,011,210
Karl’s Farm Metropolitan District No. 2, GO^(b)
Series A, 5.38%, 12/01/40		515		547,569
Series A, 5.63%, 12/01/50		1,350		1,420,456
Leyden Rock Metropolitan District No. 10, GO, Series A, 5.00%, 12/01/45		1,250		1,296,500
North Holly Metropolitan District, GO, Series A, 5.50%, 12/01/48		760		804,711
Palisade Metropolitan District No. 2, GO, Subordinate, 7.25%, 12/15/49		2,825		3,021,196
Palisade Park West Metropolitan District, GO, Series A, 5.13%, 12/01/49		1,500		1,572,630
Peak Metropolitan District No. 1, GO, 5.00%, 12/01/51^(b)		650		690,170
Pomponio Terrace Metropolitan District, GO, Series A, 5.00%, 12/01/49		1,450		1,510,465
Prairie Farm Metropolitan District, GO, Series A, 5.25%, 12/01/48		1,240		1,327,718
Pueblo Urban Renewal Authority, TA, 4.75%, 12/01/45^(b)		3,900		4,150,848
Southlands Metropolitan District No. 1, Refunding GO
Series A-1, 5.00%, 12/01/37		1,115		1,229,700
Series A-1, 5.00%, 12/01/47		3,990		4,308,681
Sterling Ranch Community Authority Board, RB, Series B, Subordinate, 7.13%, 12/15/50		750		796,117
Tallyn’s Reach Metropolitan District No. 3, GO, Subordinate, 6.75%, 11/01/38		698		718,504
Thompson Crossing Metropolitan District No. 4, Refunding GO
5.00%, 12/01/39		1,400		1,502,270
5.00%, 12/01/49		1,480		1,573,151
Timberleaf Metropolitan District, GO, Series A, 5.75%, 12/01/50		1,730		1,830,669
Westcreek Metropolitan District No. 2, GO, Series A, 5.38%, 12/01/48		800		848,208
Wild Plum Metropolitan District, GO, Series A, 5.00%, 12/01/49		595		605,793


				65,466,777

Connecticut — 1.1%
Connecticut Housing Finance Authority, Refunding RB, S/F Housing
Series C-2, AMT, 2.00%, 05/15/30		175		176,110
Series C-2, AMT, 2.05%, 11/15/30		500		502,520
Series C-2, AMT, 2.15%, 11/15/31		400		401,032
Connecticut State Health & Educational Facilities Authority, RB^(b)
Series A, 5.00%, 01/01/45		825		899,959
Series A, 5.00%, 01/01/55		1,100		1,187,175
Mashantucket Western Pequot Tribe, 7.35%, 07/01/26^(f)(g)		32,631		5,384,030
Mohegan Tribal Finance Authority, RB, 7.00%, 02/01/45^(b)		3,780		3,876,881
Mohegan Tribe of Indians of Connecticut, RB, Series A, 6.75%, 02/01/45^(b)		976		986,457
Mohegan Tribe of Indians of Connecticut, Refunding RB, Series C, 6.25%, 02/01/30^(b)		2,045		2,087,863
State of Connecticut, GO, Series A, 4.00%, 04/15/37		1,800		2,093,580


				17,595,607


2

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Delaware — 0.2%
County of Kent, RB, Series A, 5.00%, 07/01/58	$	1,500	$	1,616,790
Delaware State Economic Development Authority, RB, Series A, 5.00%, 06/01/46		1,000		1,071,960


				2,688,750

District of Columbia — 1.5%
District of Columbia Tobacco Settlement Financing Corp., RB, Series B, 0.00%, 06/15/46^(d)		43,620		7,063,561
District of Columbia Tobacco Settlement Financing Corp., RB, CAB, Series A, 0.00%, 06/15/46^(d)		40,740		8,708,583
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, 6.75%, 05/15/40		385		396,388
Metropolitan Washington Airports Authority Dulles Toll Road Revenue, Refunding RB
Series A, 5.00%, 10/01/53		3,830		3,978,681
Series B, 2nd Lien, (AGC), 0.00%, 10/01/30^(d)		3,005		2,564,046
Series B, Subordinate, 4.00%, 10/01/49		2,170		2,418,530


				25,129,789

Florida — 9.3%
Alachua County Health Facilities Authority, RB, Series A, 5.00%, 12/01/44		1,720		1,930,631
Boggy Branch Community Development District, SAB, 4.00%, 05/01/51		1,365		1,382,540
Boggy Creek Improvement District, Refunding SAB, Series 2013, 5.13%, 05/01/43		1,220		1,269,032
Capital Region Community Development District, Refunding SAB, Series A-1, 5.13%, 05/01/39		2,280		2,512,218
Capital Trust Agency, Inc., RB
4.50%, 01/01/35^(b)		2,250		2,419,380
8.25%, 01/01/44		445		8,900
8.25%, 01/01/49		950		19,000
5.00%, 07/01/49^(b)		1,280		1,398,605
5.00%, 01/01/55^(b)		4,350		4,738,237
Series A, 8.25%, 01/01/49		—		—
Series A, 5.00%, 06/15/49^(b)		500		526,395
Series A, 5.00%, 12/15/49		300		328,632
Series A, 5.75%, 06/01/54^(b)		1,925		2,011,490
Series A, 5.00%, 12/15/54		260		284,432
Series B, 0.00%, 01/01/35^(d)		3,585		1,608,195
Series B, 0.00%, 01/01/60^(d)		64,500		5,003,265
Celebration Pointe Community Development District, SAB
4.00%, 05/01/22^(b)		75		75,657
4.75%, 05/01/24		240		248,129
5.00%, 05/01/34		1,180		1,236,640
Charles Cove Community Development District, SAB
3.25%, 05/01/25		300		302,172
3.75%, 05/01/30		360		370,656
4.25%, 05/01/40		975		1,007,663
4.38%, 05/01/50		1,505		1,549,518
Charlotte County Industrial Development Authority, RB^(b)
AMT, 5.00%, 10/01/34		530		594,104
AMT, 5.00%, 10/01/49		2,510		2,690,996
City of Pompano Beach Florida, Refunding RB, 4.00%, 09/01/50		2,500		2,652,275
City of Tallahassee Florida, RB, Series A, 5.00%, 12/01/55		2,600		2,918,864


Security	Par (000)		Value


Florida (continued)
Collier County Health Facilities Authority, RB, Series A, 5.00%, 05/01/48	$	2,090	$	2,385,505
Collier County Industrial Development Authority, Refunding RB, Series A, 8.13%, 05/15/44^(b)(f)(g)		370		285,180
County of Lake Florida, RB^(b)
5.00%, 01/15/39		550		588,302
5.00%, 01/15/49		825		868,709
5.00%, 01/15/54		830		867,566
County of Osceola Florida Transportation Revenue, Refunding RB, Sereis A-1, 4.00%, 10/01/54		2,500		2,736,675
County of Osceola Florida Transportation Revenue, Refunding RB, CAB^(d)
Series A-2, 0.00%, 10/01/50		1,770		635,377
Series A-2, 0.00%, 10/01/51		2,125		732,424
Series A-2, 0.00%, 10/01/52		2,125		705,861
Series A-2, 0.00%, 10/01/53		5,675		1,813,219
Series A-2, 0.00%, 10/01/54		2,125		652,651
County of Palm Beach Florida, RB, 5.00%, 04/01/51^(b)		540		563,009
Escambia County Health Facilities Authority, Refunding RB, 4.00%, 08/15/45		6,530		7,243,925
Florida Development Finance Corp., RB
5.25%, 06/01/55^(b)		2,830		3,128,395
Class A, 5.13%, 06/15/55^(b)		10,455		10,506,543
Series A, 5.75%, 06/15/29		695		748,439
Series A, 6.00%, 06/15/34		835		899,070
Series A, 6.13%, 06/15/44		3,185		3,407,281
AMT, 5.00%, 05/01/29^(b)		3,300		3,509,451
Series A, AMT, 5.00%, 08/01/29^(a)(b)		2,240		2,316,250
Series B, AMT, 7.38%, 01/01/49^(b)		6,825		6,719,758
Grand Oaks Community Development District, SAB
4.25%, 05/01/40		915		926,483
4.50%, 05/01/52		1,015		1,033,980
Greater Orlando Aviation Authority, Refunding RB, AMT, 5.00%, 11/15/36		2,000		2,131,980
Greeneway Improvement District, SAB, 5.13%, 05/01/43		1,230		1,265,658
Hills Minneola Community Development District, SAB^(b)
4.00%, 05/01/40		1,025		1,058,835
4.00%, 05/01/50		1,500		1,525,965
Lakewood Ranch Stewardship District, SAB
4.00%, 05/01/21		54		53,797
3.90%, 05/01/23		195		198,547
4.25%, 05/01/25		80		83,244
4.25%, 05/01/26		175		181,617
4.25%, 05/01/28		535		578,421
4.75%, 05/01/29		955		1,068,416
4.95%, 05/01/29^(b)		665		751,470
4.88%, 05/01/35		265		282,792
5.00%, 05/01/38		1,175		1,304,849
3.75%, 05/01/39^(b)		570		588,941
5.30%, 05/01/39		1,090		1,245,194
5.50%, 05/01/39^(b)		670		774,828
3.75%, 05/01/40		525		538,955
4.88%, 05/01/45		545		574,752
5.13%, 05/01/46		990		1,043,737
5.10%, 05/01/48		2,545		2,802,579
5.45%, 05/01/48		1,935		2,202,204


S C H E D U L E O F I N V E S T M E N T S		3

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Florida (continued)
Lakewood Ranch Stewardship District, SAB (continued)
5.65%, 05/01/48^(b)	$	1,125	$	1,296,067
4.00%, 05/01/49^(b)		355		367,652
3.90%, 05/01/50		525		537,878
Miami-Dade County Industrial Development Authority, RB, 5.00%, 01/15/48		1,405		1,576,846
Mid-Bay Bridge Authority, RB, Series A, 7.25%, 10/01/21^(e)		1,450		1,500,938
Midtown Miami Community Development District, Refunding SAB
Series A, 5.00%, 05/01/29		1,745		1,815,393
Series A, 5.00%, 05/01/37		890		918,240
Mirada II Community Development District, SAB
3.13%, 05/01/31		500		500,200
4.00%, 05/01/51		1,500		1,515,300
North River Ranch Community Development District, SAB
Series A-1, 4.00%, 05/01/40		845		851,414
Series A-1, 4.25%, 05/01/51		1,430		1,446,659
Series A-2, 4.20%, 05/01/35		1,220		1,225,868
Series A-3, 4.75%, 05/01/40		1,615		1,615,081
Palm Beach County Health Facilities Authority, Refunding RB, Series A, 7.50%, 06/01/49		1,000		1,076,400
Pine Island Community Development District, RB, 0.00%, 11/01/24^(d)		875		735,411
Pinellas County Industrial Development Authority, RB, 5.00%, 07/01/39		220		258,201
Sandridge Community Development District, SAB
3.88%, 05/01/31		730		715,758
3.88%, 05/01/41		615		597,805
4.00%, 05/01/51		600		573,192
Santa Rosa Bay Bridge Authority, RB
6.25%, 07/01/28^(f)(g)		338		292,952
(ACA-CBI), 6.25%, 07/01/28		56		55,936
Seminole County Industrial Development Authority, Refunding RB
5.50%, 11/15/49		3,025		2,948,346
5.75%, 11/15/54		2,420		2,408,311
Southern Groves Community Development District No. 5, SAB
3.38%, 05/01/25		390		395,257
4.00%, 05/01/30		220		232,782
4.30%, 05/01/40		875		920,098
4.50%, 05/01/46		630		664,121
Tolomato Community Development District, Refunding SAB
Series 2015-2, 6.61%, 05/01/40^(c)		125		87,380
Series A-2, 4.25%, 05/01/37		915		969,488
Tolomato Community Development District, Refunding SAB, CAB, Series A-4, Convertible, 6.61%, 05/01/40^(c)		50		47,560
Tolomato Community Development District, SAB^(f)(g)
3rd Series, 6.65%, 05/01/40		105		1
Series 2015-1, 6.61%, 05/01/40^(c)		205		182,784
Series 2015-3, 6.61%, 05/01/40		135		1
Trout Creek Community Development District, SAB
5.38%, 05/01/38		670		760,350
5.50%, 05/01/49		1,700		1,913,741


Security	Par (000)		Value


Florida (continued)
V-Dana Community Development District, SAB^(b)
3.00%, 05/01/25	$	300	$	301,056
3.50%, 05/01/31		525		534,461
4.00%, 05/01/40		750		766,913
4.00%, 05/01/51		1,200		1,209,108
Viera East Community Development District, Refunding SAB, 5.00%, 05/01/26		640		667,469
Village Community Development District No. 10, SAB, 5.13%, 05/01/43		1,500		1,557,915
Village Community Development District No. 9, SAB
7.00%, 05/01/41		1,190		1,195,962
5.50%, 05/01/42		460		469,177
West Villages Improvement District, SAB
4.25%, 05/01/29		400		430,128
4.75%, 05/01/39		885		962,995
5.00%, 05/01/50		1,415		1,538,643


				153,255,698

Georgia — 1.7%
Gainesville & Hall County Hospital Authority, Refunding RB, Series A, (GTD), 5.50%, 08/15/54		555		647,163
George L Smith II Congress Center Authority, RB^(h)
4.00%, 01/01/54		1,170		1,294,675
5.00%, 01/01/54^(b)		500		544,635
Main Street Natural Gas, Inc., RB
Series A, 5.00%, 05/15/35		1,020		1,376,266
Series A, 5.00%, 05/15/36		1,020		1,383,069
Series A, 5.00%, 05/15/37		1,120		1,528,654
Series A, 5.00%, 05/15/38		615		848,762
Series A, 5.00%, 05/15/49		2,055		2,985,360
Municipal Electric Authority of Georgia, RB
4.00%, 01/01/49		4,150		4,612,850
Series A, 5.00%, 01/01/49		3,235		3,795,496
Series A, 5.00%, 01/01/59		525		612,675
Municipal Electric Authority of Georgia, Refunding RB
Subordinate, 5.00%, 01/01/45		3,000		3,759,120
Subordinate, 5.00%, 01/01/50		4,000		4,966,440


				28,355,165

Guam — 0.2%
Territory of Guam, Refunding RB
5.00%, 11/01/35		1,100		1,355,112
5.00%, 11/01/40		1,545		1,870,902


				3,226,014

Idaho — 0.4%
Idaho Health Facilities Authority, Refunding RB
3.50%, 09/01/33		375		390,075
5.00%, 09/01/37		1,000		1,103,170
Idaho Housing & Finance Association, RB^(b)
5.00%, 12/01/46		1,000		1,080,520
Series A, 6.00%, 07/01/39		370		444,018
Series A, 6.00%, 07/01/49		595		698,441
Series A, 6.00%, 07/01/54		570		664,210
Series A, 6.95%, 06/15/55		1,540		1,597,026
Power County Industrial Development Corp., RB, AMT, 6.45%, 08/01/32		265		266,182


				6,243,642

Illinois — 7.0%
Chicago Board of Education, GO
Series A, 5.00%, 12/01/38		655		786,269
Series A, 5.00%, 12/01/39		2,095		2,526,025


4

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Illinois (continued)
Chicago Board of Education, GO (continued)
Series A, 5.00%, 12/01/40	$	2,750	$	3,283,307
Series A, 5.00%, 12/01/41		5,790		6,913,434
Series A, 5.00%, 12/01/42		1,570		1,601,086
Series C, 5.25%, 12/01/39		2,250		2,479,095
Series D, 5.00%, 12/01/46		3,620		3,919,525
Series H, 5.00%, 12/01/46		725		827,733
Chicago Board of Education, Refunding GO
Series A, 5.00%, 12/01/28		530		646,897
Series A, 5.00%, 12/01/29		660		813,153
Series A, 5.00%, 12/01/30		2,210		2,711,339
Series B, 4.00%, 12/01/35		1,155		1,187,883
Series C, 5.00%, 12/01/25		1,220		1,421,727
Series C, 5.00%, 12/01/30		1,370		1,630,711
Series D, 5.00%, 12/01/31		1,500		1,769,790
Series G, 5.00%, 12/01/44		3,700		4,237,462
Chicago Board of Education, Refunding GO, CAB, Series A, 0.00%, 12/01/25^(d)		590		547,113
City of Chicago Illinois, Refunding GO
Series A, 5.25%, 01/01/32		2,315		2,540,388
Series A, 6.00%, 01/01/38		3,870		4,670,471
Series B, 5.43%, 01/01/42		9,925		10,764,754
Illinois Finance Authority, RB, Series A, 6.00%, 10/01/48		1,700		1,780,206
Illinois Finance Authority, Refunding RB
6.00%, 02/01/34		335		350,725
4.00%, 09/01/35		1,000		1,115,920
4.00%, 09/01/37		1,000		1,092,540
4.00%, 09/01/39		2,000		2,171,300
4.00%, 09/01/41		1,250		1,348,050
6.13%, 02/01/45		790		818,835
5.00%, 05/15/56^(h)		815		907,934
Series C, 5.00%, 02/15/36		1,805		2,174,213
Series C, 5.00%, 02/15/41		3,000		3,568,290
Metropolitan Pier & Exposition Authority, RB
Series A, 5.50%, 06/15/53		3,925		4,527,330
Series A, 5.00%, 06/15/57		4,555		5,277,878
Metropolitan Pier & Exposition Authority, RB, CAB, Series A, 0.00%, 12/15/52^(d)		8,775		2,969,635
Metropolitan Pier & Exposition Authority, Refunding RB, CAB^(d)
Series B, (AGM), 0.00%, 06/15/44		3,455		1,728,329
Series B, 0.00%, 12/15/54		41,770		12,870,172
Quad Cities Regional Economic Development Authority, Refunding RB, 4.75%, 10/01/32		675		710,849
State of Illinois, GO
5.50%, 05/01/30		1,235		1,544,615
4.00%, 03/01/38		2,250		2,506,388
5.00%, 02/01/39		510		546,363
4.00%, 03/01/39		2,100		2,331,042
5.50%, 05/01/39		2,460		3,055,222
4.00%, 03/01/40		2,300		2,543,455
Series A, 5.00%, 04/01/35		1,460		1,567,646
Series A, 5.00%, 04/01/38		2,190		2,347,198


				115,132,297

Indiana — 1.1%
City of Anderson Indiana, RB, 5.38%, 01/01/40		1,540		1,568,382


Security	Par (000)		Value


Indiana (continued)
City of Valparaiso Indiana, RB
AMT, 6.75%, 01/01/34	$	525	$	567,845
AMT, 7.00%, 01/01/44		1,270		1,380,376
City of Vincennes Indiana, Refunding RB, 6.25%, 01/01/29^(b)		2,550		2,551,530
Indiana Finance Authority, RB
Series A, AMT, 6.75%, 05/01/39		2,785		3,455,377
Series A, AMT, 5.00%, 07/01/44		370		393,632
Series A, AMT, 5.00%, 07/01/48		1,230		1,322,767
Series A, AMT, 5.25%, 01/01/51		2,500		2,697,500
Indiana Finance Authority, Refunding RB, 5.00%, 03/01/22^(e)		725		756,567
Indiana Housing & Community Development Authority, RB, 5.38%, 10/01/40^(b)		3,175		3,246,469


				17,940,445

Iowa — 0.7%
Iowa Finance Authority, RB, Series A, 5.00%, 05/15/48		2,360		2,668,051
Iowa Finance Authority, Refunding RB, Series A, 5.25%, 12/01/50^(a)		595		637,340
Iowa Higher Education Loan Authority, Refunding RB, 5.50%, 11/01/51		3,000		3,318,330
Iowa Tobacco Settlement Authority, Refunding RB
Series C, 5.38%, 06/01/38		3,075		3,112,607
Series C, 5.50%, 06/01/42		2,030		2,054,644


				11,790,972

Kentucky — 0.2%
Kentucky Economic Development Finance Authority, Refunding RB, Series B, (NPFGC), 0.00%, 10/01/24^(d)		250		241,035
Kentucky Public Transportation Infrastructure Authority, RB, Series A, 6.00%, 07/01/53		3,000		3,304,290


				3,545,325

Louisiana — 1.8%
Juban Crossing Economic Development District, Refunding RB, Series C, 7.00%, 09/15/44^(b)		3,055		2,932,861
Louisiana Local Government Environmental Facilities & Community Development Authority, RB, 5.00%, 07/01/54^(b)		1,990		2,027,909
Louisiana Public Facilities Authority, RB^(b)
5.00%, 06/01/41		840		888,510
5.25%, 06/01/51		1,830		1,944,229
5.25%, 06/01/60		3,385		3,567,553
Series A, 5.00%, 04/01/49		500		523,830
Louisiana Public Facilities Authority, Refunding RB, 4.00%, 04/01/50		12,320		13,931,949
Parish of St. James Louisiana, RB, 2nd Series, 6.35%, 07/01/40^(b)		3,160		3,944,438


				29,761,279

Maryland — 1.2%
City of Baltimore Maryland, Refunding RB
5.00%, 09/01/46		1,500		1,538,535
Series A, 4.00%, 09/01/27		325		338,861
County of Frederick Maryland, Refunding TA, 4.63%, 07/01/43^(b)		5,065		5,751,611
Maryland Economic Development Corp., RB, 5.00%, 07/01/56		985		1,142,728


S C H E D U L E O F I N V E S T M E N T S		5

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Maryland (continued)
Maryland Economic Development Corp., Refunding RB, 5.00%, 07/01/39	$	950	$	1,014,220
Maryland Economic Development Corp., TA, 4.00%, 09/01/50		605		641,052
Maryland Health & Higher Educational Facilities Authority, RB, Series A, 7.00%, 03/01/55^(b)		8,165		9,172,398


				19,599,405

Massachusetts — 0.6%
Massachusetts Development Finance Agency, RB
Series B, 0.00%, 11/15/56^(d)		94		13,807
Series D, 4.00%, 07/01/45		715		758,322
Massachusetts Development Finance Agency, Refunding RB
4.00%, 10/01/32^(b)		355		382,474
4.13%, 10/01/42^(b)		855		918,911
Series A, 5.00%, 07/01/38		1,200		1,452,900
Series A, 5.00%, 07/01/39		3,055		3,687,446
Series A, 5.00%, 07/01/44		2,000		2,385,940


				9,599,800

Michigan — 0.5%
Advanced Technology Academy, Refunding RB
3.50%, 11/01/24		250		255,720
3.88%, 11/01/29		150		158,679
5.00%, 11/01/34		400		444,420
5.00%, 11/01/44		160		173,389
City of Detroit Michigan, GO
5.00%, 04/01/34		485		566,320
5.00%, 04/01/35		485		564,661
5.00%, 04/01/36		340		394,852
5.00%, 04/01/37		545		631,175
5.00%, 04/01/38		240		277,241
Kentwood Economic Development Corp., Refunding RB, 5.63%, 11/15/41		1,000		1,038,530
Michigan Finance Authority, RB^(e)
Series C-2, AMT, Senior Lien, 5.00%, 07/01/22		350		370,265
Series C-1, Senior Lien, 5.00%, 07/01/22		800		848,088
Michigan Strategic Fund, RB, AMT, 5.00%, 06/30/48		2,030		2,420,694


				8,144,034

Minnesota — 1.0%
City of Cologne Minnesota,RB, Series A, 5.00%, 07/01/45		2,065		2,162,530
City of Deephaven Minnesota, Refunding RB, Series A, 5.25%, 07/01/40		500		539,010
City of Minneapolis Minnesota, RB
Series A, 5.00%, 07/01/55		1,405		1,491,422
Series A, 5.75%, 07/01/55		3,435		3,779,634
Duluth Economic Development Authority, Refunding RB
Series A, 4.25%, 02/15/48		1,925		2,140,619
Series A, 5.25%, 02/15/53		3,850		4,579,459
Housing & Redevelopment Authority of The City of St. Paul Minnesota, RB 5.00%, 07/01/49		555		608,213


Security	Par (000)		Value


Minnesota (continued)
Housing & Redevelopment Authority of The City of St. Paul Minnesota, RB (continued) 5.00%, 07/01/55	$	870	$	944,777
Housing & Redevelopment Authority of The City of St. Paul Minnesota, Refunding RB, Series A, 6.63%, 09/01/21^(e)		500		513,160


				16,758,824

Missouri — 0.8%
Health & Educational Facilities Authority of the State of Missouri, Refunding RB, Series A, 4.00%, 11/15/48		3,650		4,052,668
Industrial Development Authority of the City of St. Louis Missouri, Refunding RB
Series A, 4.38%, 11/15/35		1,020		961,024
Series A, 4.75%, 11/15/47		1,135		1,066,923
Kansas City Industrial Development Authority, Refunding RB^(b)(f)(g)
5.75%, 11/15/36		1,350		462,985
6.00%, 11/15/51		110		37,725
Kansas City Land Clearance Redevelopment Authority, TA^(b)
Series B, 4.38%, 02/01/31		3,245		3,459,786
Series B, 5.00%, 02/01/40		1,240		1,319,000
Poplar Bluff Regional Transportation Development District, RB, 4.75%, 12/01/42		2,200		2,240,788


				13,600,899

Nebraska — 0.6%
Central Plains Energy Project, RB, 5.00%, 09/01/42		780		830,021
Central Plains Energy Project, Refunding RB, Series A, 5.00%, 09/01/42		6,090		8,569,909


				9,399,930

Nevada — 0.3%
City of Las Vegas Nevada Special Improvement District No. 815, SAB, 5.00%, 12/01/49		810		892,409
County of Clark Nevada, Refunding SAB
4.00%, 08/01/22		495		517,131
4.00%, 08/01/23		305		318,594
Tahoe-Douglas Visitors Authority, RB
5.00%, 07/01/40		825		948,519
5.00%, 07/01/45		1,025		1,164,472
5.00%, 07/01/51		1,100		1,238,820


				5,079,945

New Hampshire — 1.0%
New Hampshire Business Finance Authority, RB
Series A, 4.13%, 08/15/40		1,435		1,448,833
Series A, 4.25%, 08/15/46		1,610		1,614,379
Series A, 4.50%, 08/15/55		3,350		3,359,782
New Hampshire Business Finance Authority, Refunding RB
4.00%, 01/01/41		2,200		2,410,694
Series B, 4.63%, 11/01/42^(b)		4,650		4,827,584
Series C, AMT, 4.88%, 11/01/42^(b)		2,515		2,624,604


				16,285,876

New Jersey — 4.6%
Casino Reinvestment Development Authority, Inc., Refunding RB, 5.25%, 11/01/44		5,750		6,033,130


6

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


New Jersey (continued)
Industrial Pollution Control Financing Authority of Gloucester County, Refunding RB, Series A, AMT, 5.00%, 12/01/24	$	1,150	$	1,195,828
New Jersey Economic Development Authority, RB
4.00%, 11/01/38		1,455		1,620,826
4.00%, 11/01/39		1,165		1,294,233
6.00%, 10/01/43		970		1,071,414
Series A, 5.00%, 07/01/32		235		247,208
Series A, 5.00%, 07/01/37		375		389,310
Series A, 5.00%, 01/01/48		1,110		1,146,242
Series A, 5.25%, 11/01/54^(b)		3,955		3,960,418
Series B, 5.00%, 06/15/43		3,755		4,437,284
Series EEE, 5.00%, 06/15/43		5,550		6,544,782
AMT, 5.13%, 09/15/23		1,520		1,617,341
AMT, 5.38%, 01/01/43		1,360		1,501,331
Series B, AMT, 6.50%, 04/01/31		2,750		2,929,383
New Jersey Health Care Facilities Financing Authority, Refunding RB
5.00%, 07/01/32		1,140		1,381,372
5.00%, 07/01/33		1,450		1,751,310
New Jersey Transportation Trust Fund Authority, RB
Series AA, 5.25%, 06/15/41		1,265		1,441,936
Series AA, 5.00%, 06/15/44		1,005		1,107,560
Series BB, 4.00%, 06/15/50		10,940		11,915,629
Series BB, 5.00%, 06/15/50		8,560		9,989,263
Series S, 5.25%, 06/15/43		4,095		4,952,002
New Jersey Transportation Trust Fund Authority, Refunding RB, Series A, 5.00%, 12/15/36		1,195		1,439,676
South Jersey Port Corp., RB, Series B, AMT, 5.00%, 01/01/36		575		665,568
Tobacco Settlement Financing Corp., Refunding RB
Series A, 5.25%, 06/01/46		900		1,066,923
Sub-Series B, 5.00%, 06/01/46		4,430		5,137,205


				74,837,174

New Mexico — 0.1%
New Mexico Hospital Equipment Loan Council, Refunding RB, 5.50%, 07/01/42		2,030		2,143,132


New York — 6.5%
Build NYC Resource Corp., Refunding RB, AMT, 5.00%, 01/01/35^(b)		1,215		1,346,925
Chautauqua Tobacco Asset Securitization Corp., Refunding RB, 5.00%, 06/01/48		4,475		4,585,085
City of New York Water & Sewer System, RB, 3rd Series, 5.40%, 01/01/22^(a)(f)(g)		208		187,423
Erie Tobacco Asset Securitization Corp., Refunding RB, Series A, 5.00%, 06/01/45		3,210		3,238,184
Huntington Local Development Corp., RB, 5.25%, 07/01/56		585		607,183
Metropolitan Transportation Authority, Refunding RB
Series C-1, 4.75%, 11/15/45		4,115		4,847,182
Series C-1, 5.00%, 11/15/50		1,340		1,604,342
Series C-1, 5.25%, 11/15/55		1,980		2,407,007
Monroe County Industrial Development Corp., Refunding RB, 4.00%, 12/01/39		1,200		1,381,164
New York City Industrial Development Agency, Refunding RB
Class A, (AGM), 3.00%, 01/01/37		755		801,591
Class A, (AGM), 2.00%, 01/01/38		3,000		2,865,570
Class A, (AGM), 3.00%, 01/01/39		755		797,439


Security	Par (000)		Value


New York (continued)
New York City Industrial Development Agency, Refunding RB (continued)
Class A, (AGM), 3.00%, 01/01/40	$	525	$	554,573
Class A, (AGM), 3.00%, 01/01/46		2,450		2,535,407
New York Counties Tobacco Trust IV, Refunding RB
Series A, 6.25%, 06/01/41^(b)		8,000		8,101,200
Series A, 5.00%, 06/01/42		4,520		4,558,149
Series A, 5.00%, 06/01/45		1,695		1,709,255
New York Counties Tobacco Trust VI, Refunding RB
Series A-2-B, 5.00%, 06/01/45		4,010		4,270,209
Series A-2-B, 5.00%, 06/01/51		6,865		7,181,133
New York Liberty Development Corp., Refunding RB^(b)
Series 1, Class 1, 5.00%, 11/15/44		15,115		16,503,313
Series 2, Class 2, 5.15%, 11/15/34		450		498,870
Series 2, Class 2, 5.38%, 11/15/40		1,070		1,198,282
New York State Dormitory Authority, Refunding RB^(b)
5.00%, 12/01/33		590		687,787
5.00%, 12/01/35		785		909,509
New York State Housing Finance Agency, RB, M/F Housing, Series L-1, (SONYMA), 2.60%, 11/01/50		3,750		3,739,537
New York Transportation Development Corp., ARB, Series A, AMT, 5.25%, 01/01/50		3,000		3,362,220
New York Transportation Development Corp., RB
AMT, 5.00%, 10/01/35		1,295		1,591,840
AMT, 4.00%, 01/01/36		5,000		5,511,000
AMT, 5.00%, 10/01/40		3,650		4,436,502
AMT, 4.00%, 10/31/46		2,220		2,483,403
AMT, 4.00%, 04/30/53		1,145		1,277,980
New York Transportation Development Corp., Refunding ARB, AMT, 5.38%, 08/01/36		3,665		4,408,152
Niagara Area Development Corp., Refunding RB, Series A, AMT, 4.75%, 11/01/42^(b)		530		554,083
Triborough Bridge & Tunnel Authority, RB, Series A, 4.00%, 11/15/54		670		764,624
Westchester County Healthcare Corp., RB, Series A, Senior Lien, 5.00%, 11/01/44		1,319		1,466,551
Westchester County Local Development Corp., Refunding RB, 5.13%, 07/01/55		1,100		1,117,941
Westchester Tobacco Asset Securitization Corp., Refunding RB
Sub-Series C, 4.00%, 06/01/42		935		1,007,088
Sub-Series C, 5.13%, 06/01/51		2,000		2,205,860


				107,303,563

North Carolina — 0.2%
North Carolina Turnpike Authority, RB, Senior Lien, 4.00%, 01/01/55		3,000		3,329,400


North Dakota — 0.1%
County of Cass North Dakota, Refunding RB, Series B, 5.25%, 02/15/58		1,785		2,117,313


Ohio — 2.3%
Buckeye Tobacco Settlement Financing Authority, Refunding RB, Series B-2, Class 2, 5.00%, 06/01/55		5,515		6,210,111
Cleveland-Cuyahoga County Port Authority, RB
4.00%, 07/01/46		190		218,255
4.00%, 07/01/51		260		297,734


S C H E D U L E O F I N V E S T M E N T S		7

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Ohio (continued)
County of Hamilton Ohio, Refunding RB, 5.00%, 01/01/46	$	1,435	$	1,520,325
County of Hardin Ohio, Refunding RB
5.00%, 05/01/30		620		667,777
5.25%, 05/01/40		1,235		1,292,773
5.50%, 05/01/50		2,895		3,012,826
Franklin County Convention Facilities Authority, RB
5.00%, 12/01/44		1,800		2,075,544
5.00%, 12/01/51		4,000		4,589,280
Hickory Chase Community Authority, Refunding RB, 5.00%, 12/01/40^(b)		1,890		1,983,574
Ohio Air Quality Development Authority, RB, AMT, 5.00%, 07/01/49^(b)		5,000		5,409,700
Port of Greater Cincinnati Development Authority, RB, 4.25%, 12/01/50^(b)		1,100		1,083,005
Southern Ohio Port Authority, RB, Series A, AMT, 7.00%, 12/01/42^(b)		8,980		10,168,144


				38,529,048

Oklahoma — 1.8%
Norman Regional Hospital Authority, RB, 4.00%, 09/01/45		3,565		3,906,634
Oklahoma Development Finance Authority, RB
7.25%, 09/01/51^(b)		14,090		14,184,826
Series B, 5.00%, 08/15/38		4,585		5,549,821
Series B, 5.25%, 08/15/43		4,130		5,024,228
Tulsa County Industrial Authority, Refunding RB, 5.25%, 11/15/37		1,050		1,116,958


				29,782,467

Oregon — 0.6%
Medford Hospital Facilities Authority, Refunding RB
Series A, 4.00%, 08/15/50		4,845		5,475,480
Series A, 5.00%, 08/15/50		2,000		2,504,280
Oregon State Facilities Authority, RB^(b)
Series A, 5.00%, 06/15/49		915		862,872
Series A, 5.25%, 06/15/55		505		486,724


				9,329,356

Pennsylvania — 1.9%
Allentown Neighborhood Improvement Zone Development Authority, Refunding RB
Series A, 5.00%, 05/01/35		1,185		1,229,307
Series A, 5.00%, 05/01/42		2,730		2,817,415
Berks County Industrial Development Authority, Refunding RB, 4.00%, 11/01/47		2,260		2,103,744
Berks County Municipal Authority, Refunding RB
Series A, 5.00%, 02/01/31		750		834,247
Series A, 5.00%, 02/01/32		790		880,700
Bucks County Industrial Development Authority, RB
4.00%, 07/01/46		275		292,534
4.00%, 07/01/51		200		212,216
City of Philadelphia Water & Wastewater Revenue, RB, Series A, 5.00%, 11/01/50		6,000		7,608,720
East Hempfield Township Industrial Development Authority, RB
5.00%, 07/01/34		1,000		1,022,110
5.00%, 07/01/46		1,750		1,764,000


Security	Par (000)		Value


Pennsylvania (continued)
Montgomery County Higher Education and Health Authority, Refunding RB, Series A, 4.00%, 09/01/49	$	880	$	964,938
Montgomery County Industrial Development Authority, Refunding RB
5.00%, 12/01/46		1,470		1,597,552
5.38%, 01/01/50		1,865		1,881,449
Northampton County Industrial Development Authority, TA, 7.00%, 07/01/32		1,120		1,186,550
Pennsylvania Economic Development Financing Authority, RB, AMT, 5.00%, 06/30/42		895		1,020,103
Pennsylvania Economic Development Financing Authority, Refunding RB, AMT, 5.50%, 11/01/44		5,390		5,673,298


				31,088,883

Puerto Rico — 12.6%
Children’s Trust Fund, RB^(d)
Series A, 0.00%, 05/15/57		63,950		4,406,155
Series B, 0.00%, 05/15/57		199,810		10,695,829
Children’s Trust Fund, Refunding RB, Series B, 0.00%, 05/15/55^(d)		2,000		181,120
Commonwealth of Puerto Rico, GO^(f)(g)
Series A, 5.25%, 07/01/22		335		291,607
Series A, 5.00%, 07/01/23		1,250		1,088,086
Series A, 5.13%, 07/01/31		215		187,151
Series A, 6.00%, 07/01/38		1,210		1,077,656
Series B, 5.25%, 07/01/17		1,060		905,195
Commonwealth of Puerto Rico, Refunding GO
Series A, 5.25%, 07/01/16^(f)(g)		1,135		969,242
Series A, 5.50%, 07/01/18^(f)(g)		200		170,792
Series A, 5.50%, 07/01/26		1,000		827,686
Series A, 8.00%, 07/01/35^(f)(g)		22,191		17,412,102
Series A, 5.50%, 07/01/39^(f)(g)		4,285		3,546,634
Series A, 6.50%, 07/01/40^(f)(g)		2,610		2,254,387
Series A, 5.00%, 07/01/41^(f)(g)		7,715		6,096,995
Series C, 6.00%, 07/01/39^(f)(g)		168		149,625
Series C, 6.50%, 07/01/40^(f)(g)		400		345,500
Series D, 5.75%, 07/01/41^(f)(g)		385		329,444
Puerto Rico Commonwealth Aqueduct & Sewer Authority, RB
Series A, Senior Lien, 5.75%, 07/01/37		1,565		1,653,689
Series A, Senior Lien, 5.25%, 07/01/42		4,890		5,137,727
Puerto Rico Commonwealth Aqueduct & Sewer Authority, Refunding RB^(b)
Series A, Senior Lien, 5.00%, 07/01/35		4,890		5,729,466
Series A, Senior Lien, 5.00%, 07/01/47		8,605		9,952,715
Puerto Rico Electric Power Authority, RB^(f)(g)
7.50%, 01/01/22^(a)		4,430		4,100,737
Series A, 7.25%, 07/01/30		250		231,422
Series A, 7.00%, 07/01/33		8,735		8,085,885
Series A, 6.75%, 07/01/36		5,165		4,781,178
Series A, 7.00%, 07/01/40		1,000		925,688
Series A, 5.00%, 07/01/42		2,315		2,089,227
Series A, 5.05%, 07/01/42		1,080		974,672
Series A, 7.00%, 07/01/43		775		717,408
Series A-3, 10.00%, 07/01/19		748		692,064
Series B-3, 10.00%, 07/01/19		748		692,064
Series C-1, 5.40%, 01/01/18		2,054		1,853,840
Series C-2, 5.40%, 07/01/18		2,054		1,854,140


8

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Puerto Rico (continued)
Puerto Rico Electric Power Authority, RB^(f)(g)(continued)
Series C-4, 5.40%, 07/01/20	$	208	$	187,423
Series CCC, 5.00%, 07/01/22		715		645,269
Series CCC, 5.00%, 07/01/25		620		559,534
Series CCC, 5.25%, 07/01/26		590		532,460
Series CCC, 5.25%, 07/01/28		1,945		1,687,141
Series TT, 5.00%, 07/01/25		3,270		2,951,090
Series TT, 5.00%, 07/01/26		455		410,626
Series TT, 5.00%, 07/01/32		—		—
Series WW, 5.50%, 07/01/17		475		428,675
Series WW, 5.50%, 07/01/18		415		374,527
Series WW, 5.50%, 07/01/19		335		302,329
Series WW, 5.38%, 07/01/24		815		735,516
Series WW, 5.25%, 07/01/25		1,940		1,750,800
Series WW, 5.25%, 07/01/33		315		284,279
Series WW, 5.50%, 07/01/38		415		374,527
Series XX, 5.25%, 07/01/27		230		207,569
Series XX, 5.25%, 07/01/35		705		636,244
Series XX, 5.75%, 07/01/36		200		180,495
Series XX, 5.25%, 07/01/40		8,385		7,567,244
Puerto Rico Electric Power Authority, Refunding RB
Series AAA, 5.25%, 07/01/22^(f)(g)		765		690,393
Series AAA, 5.25%, 07/01/24^(f)(g)		170		153,421
Series AAA, 5.25%, 07/01/25		1,865		1,603,900
Series AAA, 5.25%, 07/01/25^(f)(g)		1,695		1,529,693
Series AAA, 5.25%, 07/01/28		2,000		1,720,000
Series AAA, 5.25%, 07/01/28^(f)(g)		1,655		1,493,594
Series AAA, 5.25%, 07/01/29^(f)(g)		190		171,470
Series UU, 1.00%, 07/01/17^(a)		2,520		2,104,732
Series UU, 1.00%, 07/01/17^(a)(f)(g)		140		114,100
Series UU, 1.00%, 07/01/18^(a)(f)(g)		125		101,875
Series UU, 1.00%, 07/01/20^(a)(f)(g)		1,135		947,964
Series UU, 0.84%, 07/01/31^(a)(f)(g)		1,345		1,123,359
Series ZZ, 5.00%, 07/01/17^(f)(g)		330		297,816
Series ZZ, 5.25%, 07/01/19^(f)(g)		1,050		947,598
Series ZZ, 5.25%, 07/01/21^(f)(g)		90		81,223
Series ZZ, 5.25%, 07/01/23^(f)(g)		370		318,200
Series ZZ, 5.25%, 07/01/24		4,345		3,736,700
Series ZZ, 5.25%, 07/01/24^(f)(g)		705		636,244
Series ZZ, 5.25%, 07/01/25^(f)(g)		265		239,156
Series ZZ, 5.25%, 07/01/26^(f)(g)		85		76,710
Series ZZ, 5.00%, 07/01/28^(f)(g)		345		311,354
Puerto Rico Public Buildings Authority, Refunding RB^(f)(g)
Series F, (GTD), 5.25%, 07/01/24		1,495		1,438,715
Series G, (GTD), 4.75%, 07/01/32		1,230		1,183,692
Series M, (GTD), 6.25%, 07/01/31		2,000		1,997,500
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB
Series A-1, Restructured, 4.75%, 07/01/53		12,864		13,936,729
Series A-1, Restructured, 5.00%, 07/01/58		13,313		14,635,780
Series A-2, Restructured, 4.33%, 07/01/40		9,257		9,910,452
Series A-2, Restructured, 4.54%, 07/01/53		1,564		1,673,762
Series A-2, Restructured, 4.78%, 07/01/58		7,333		7,951,099
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB, CAB^(d)
Series A-1, Restructured, 0.00%, 07/01/29		2,914		2,414,599
Series A-1, Restructured, 0.00%, 07/01/31		1,895		1,449,410
Series A-1, Restructured, 0.00%, 07/01/33		679		481,092


Security	Par (000)		Value


Puerto Rico (continued)
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB, CAB^(d)(continued)
Series A-1, Restructured, 0.00%, 07/01/46	$	29,376	$	8,969,080
Series A-1, Restructured, 0.00%, 07/01/51		6,487		1,434,795
Series B-1, Restructured, 0.00%, 07/01/46		2,066		631,266


				206,730,349

Rhode Island — 1.2%
Tobacco Settlement Financing Corp., Refunding RB
Series A, 5.00%, 06/01/35		1,005		1,143,208
Series A, 5.00%, 06/01/40		5,500		6,106,540
Series B, 4.50%, 06/01/45		6,350		6,849,173
Series B, 5.00%, 06/01/50		5,650		6,284,778


				20,383,699

South Carolina — 0.7%
County of Dorchester South Carolina, SAB, 6.00%, 10/01/51^(b)		2,240		2,429,303
South Carolina Jobs-Economic Development Authority, RB
Series A, 5.00%, 11/15/42		585		641,236
Series A, 5.00%, 11/15/54		280		302,212
South Carolina Jobs-Economic Development Authority, Refunding RB
4.00%, 11/15/27		670		704,626
Series A, 5.00%, 05/01/48		5,825		6,792,940


				10,870,317

Tennessee — 0.9%
Chattanooga Health Educational & Housing Facility Board, Refunding RB, Series A, 4.00%, 08/01/44		410		463,431
Franklin Health & Educational Facilities Board, Refunding RB, Series A, 7.50%, 06/01/47^(b)(f)(g)		4,060		1,219,795
Knox County Health Educational & Housing Facility Board, Refunding RB, 5.00%, 04/01/36		560		654,002
Memphis-Shelby County Industrial Development Board, Refunding TA
Series A, 5.50%, 07/01/37		1,650		1,668,942
Series A, 5.63%, 01/01/46		1,875		1,870,537
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board, RB, Series A, 5.00%, 07/01/40		925		1,091,056
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board, Refunding RB, Series A, 4.00%, 10/01/49		1,635		1,703,278
Metropolitan Government Nashville & Davidson County Health & Educational Facs Bd, Refunding RB, Series A, 5.25%, 10/01/58		5,335		6,075,711
Nashville Metropolitan Development & Housing Agency, TA, 5.13%, 06/01/36^(b)		500		563,005


				15,309,757

Texas — 5.0%
Arlington Higher Education Finance Corp., RB
5.00%, 01/15/51		2,045		2,126,166
5.63%, 08/15/54^(b)		6,260		6,475,970
Series A, 5.88%, 03/01/24		340		361,876
Series A, 4.63%, 08/15/46		830		833,353
Arlington Higher Education Finance Corp., Refunding RB, 5.00%, 08/15/51		1,000		1,054,570
Brazoria County Industrial Development Corp., RB, AMT, 7.00%, 03/01/39		1,610		1,666,849


S C H E D U L E O F I N V E S T M E N T S		9

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Texas (continued)
Central Texas Regional Mobility Authority, Refunding RB, 0.00%, 01/01/31^(d)	$	4,000	$	3,268,960
Central Texas Regional Mobility Authority, Refunding RB, CAB^(d)
0.00%, 01/01/28		3,000		2,698,770
0.00%, 01/01/29		500		436,370
0.00%, 01/01/30		1,330		1,122,560
City of Houston Texas Airport System Revenue, RB, AMT, 5.00%, 07/15/28		2,725		3,224,819
City of Houston Texas Airport System Revenue, Refunding ARB, AMT, 5.00%, 07/15/27		615		712,170
City of Houston Texas Airport System Revenue, Refunding RB
Series A, AMT, 6.63%, 07/15/38		1,110		1,129,125
Series C, AMT, 5.00%, 07/15/27		3,925		4,541,853
Fort Bend County Industrial Development Corp., RB, Series B, 4.75%, 11/01/42		3,380		3,546,127
Harris County Cultural Education Facilities Finance Corp., Refunding RB
Series A, 5.00%, 01/01/38		510		530,477
Series A, 5.00%, 01/01/43		520		534,856
Series A, 5.13%, 01/01/48		1,535		1,572,607
Harris County-Houston Sports Authority, Refunding RB, Series G, Senior Lien, (NPFGC), 0.00%, 11/15/41^(d)		350		132,171
Hemphill County Hospital District, GO
4.63%, 02/01/39		1,500		1,433,190
4.75%, 02/01/45		2,500		2,332,625
Houston Higher Education Finance Corp., RB, 4.00%, 10/01/51		1,400		1,463,882
Houston Higher Education Finance Corp., Refunding RB, 6.50%, 05/15/21^(e)		535		538,809
Mission Economic Development Corp., Refunding RB, AMT, Senior Lien, 4.63%, 10/01/31^(b)		1,385		1,470,801
New Hope Cultural Education Facilities Finance Corp., RB
5.00%, 08/15/39^(b)		420		437,900
5.00%, 08/15/49^(b)		825		849,932
Series A, 5.88%, 04/01/23^(e)		890		989,680
Series A, 6.00%, 04/01/23^(e)		1,355		1,510,120
Series A, 10.00%, 12/01/25^(b)		3,165		3,150,124
Series A, 5.00%, 07/01/57		3,000		3,127,050
New Hope Cultural Education Facilities Finance Corp., Refunding RB^(b)
Series A, 5.00%, 08/15/36		2,520		2,537,464
Series A, 5.00%, 08/15/46		695		698,732
Newark Higher Education Finance Corp., RB
5.00%, 06/15/48		1,500		1,526,520
Series A, 5.50%, 08/15/35^(b)		375		430,365
Series A, 5.75%, 08/15/45^(b)		735		834,372
Port Beaumont Navigation District, Refunding RB, Series A, AMT, 4.00%, 01/01/50^(b)		3,600		3,711,600
Red River Health Facilities Development Corp., RB
5.13%, 01/01/41		600		604,704
7.25%, 12/15/42^(f)(g)		1,330		879,883
Tarrant County Cultural Education Facilities Finance Corp., RB, Series B, 5.00%, 07/01/48		8,560		10,231,169
Texas Transportation Commission, RB, CAB^(d) 0.00%, 08/01/46		2,580		863,861


Security	Par (000)		Value


Texas (continued)
Texas Transportation Commission, RB, CAB^(d)(continued)
0.00%, 08/01/47	$	3,850	$	1,226,880
0.00%, 08/01/48		4,070		1,231,704
0.00%, 08/01/49		3,825		1,098,349
0.00%, 08/01/50		5,485		1,486,106
0.00%, 08/01/51		3,230		826,848
0.00%, 08/01/52		3,230		780,659
0.00%, 08/01/53		290		66,268


				82,309,246

Utah^(b)— 0.1%
Utah Charter School Finance Authority, RB
Series A, 5.00%, 06/15/41		590		644,321
Series A, 5.00%, 06/15/52		750		801,945


				1,446,266

Vermont^(b)— 0.4%
East Central Vermont Telecommunications District, RB
Series A, 4.75%, 12/01/40		2,850		2,901,955
Series A, 4.50%, 12/01/50		3,000		3,009,480


				5,911,435

Virginia — 1.0%
Hanover County Economic Development Authority, Refunding RB, Series A, 5.00%, 07/01/47		1,015		1,037,756
Henrico County Economic Development Authority, Refunding RB, 4.00%, 10/01/50		1,250		1,318,087
Lower Magnolia Green Community Development Authority, SAB^(b)
5.00%, 03/01/35		490		526,598
5.00%, 03/01/45		505		535,916
Norfolk Redevelopment & Housing Authority, RB
Series A, 5.00%, 01/01/49		1,250		1,315,313
Series A, 5.25%, 01/01/54		3,750		3,991,500
Salem Economic Development Authority, Refunding RB, 4.00%, 04/01/45		830		890,773
Virginia Beach Development Authority, Refunding RB, 4.00%, 09/01/48		2,885		3,029,221
Virginia Small Business Financing Authority, RB, AMT, Senior Lien, 6.00%, 01/01/37		3,360		3,576,048


				16,221,212

Washington — 0.7%
Greater Wenatchee Regional Events Center Public Facilities District, Refunding RB, Series A, 5.50%, 09/01/42		1,005		1,019,563
Washington Economic Development Finance Authority, RB, AMT, 5.63%, 12/01/40^(b)		3,470		3,881,091
Washington Health Care Facilities Authority, Refunding RB, Series A, 4.00%, 08/01/44		885		994,306
Washington State Housing Finance Commission, RB^(b)
5.00%, 07/01/50		620		679,935
5.00%, 07/01/56		700		757,806
Washington State Housing Finance Commission, Refunding RB^(b) 5.75%, 01/01/35		355		380,773


10

Schedule of Investments (unaudited) (continued)

March 31, 2021

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)(continued)
6.00%, 01/01/45	$	940	$	1,005,791
5.00%, 01/01/48		2,410		2,717,540


				11,436,805

Wisconsin — 3.8%
Public Finance Authority, RB
5.00%, 12/01/35^(b)		200		223,246
5.00%, 06/15/39		310		359,585
5.00%, 06/15/41^(b)		925		958,966
5.00%, 01/01/42^(b)		1,555		1,601,666
5.00%, 12/01/45^(b)		280		306,135
6.85%, 11/01/46^(b)		1,325		1,382,637
7.00%, 11/01/46^(b)		805		845,677
5.00%, 06/15/49		955		1,085,434
5.63%, 06/15/49^(b)		6,000		5,878,620
5.00%, 04/01/50^(b)		315		356,337
5.00%, 06/15/53		645		731,095
5.00%, 06/15/55^(b)		13,945		13,966,000
5.00%, 12/01/55^(b)		955		1,036,242
5.00%, 01/01/56^(b)		3,790		3,847,305
Series A, 6.25%, 10/01/31^(b)		910		956,738
Series A, 5.00%, 06/01/40^(b)		750		814,522
Series A, 5.38%, 06/01/44^(b)		1,215		1,218,220
Series A, 5.38%, 07/15/47^(b)		1,595		1,762,204
Series A, 7.00%, 10/01/47^(b)		910		945,344
Series A, 5.00%, 06/01/49^(b)		1,340		1,431,415
Series A, 5.63%, 06/15/49^(b)		8,105		8,426,768
Series A, 5.50%, 06/01/54^(b)		1,500		1,435,365
Series A-1, 4.50%, 01/01/35^(b)		895		963,557
Series A-1, 5.50%, 12/01/48^(b)(f)(g)		38		12,653
Series A-1, 5.00%, 01/01/55^(b)		2,470		2,711,023
Series B, 0.00%, 01/01/35^(b)(d)		1,230		550,216
Series B, 0.00%, 01/01/60^(b)(d)		31,635		2,470,377
Public Finance Authority, Refunding RB^(b)
5.00%, 03/01/52		1,300		1,351,792
Series A, 5.00%, 10/01/34		280		315,837
Series A, 5.00%, 10/01/39		680		754,691
Wisconsin Health & Educational Facilities Authority, Refunding RB
5.00%, 11/01/46		1,130		1,182,488
5.00%, 11/01/54		1,880		1,949,203
Wisconsin Housing & Economic Development Authority, RB, M/F Housing, Series A, 4.70%, 07/01/47		740		793,606


				62,624,964


Total Municipal Bonds — 90.2% (Cost: $1,361,596,784)				1,484,261,754


Municipal Bonds Transferred to Tender Option Bond Trusts⁽ⁱ⁾

Georgia — 0.2%
Dalton Whitfield County Joint Development Authority, RB, 4.00%, 08/15/48		3,140		3,494,380


Illinois — 1.0%
Illinois Finance Authority, RB, Series A, (AGM), 6.00%, 08/15/41		2,480		2,530,270


Security	Par (000)		Value


Illinois (continued)
Illinois Finance Authority, Refunding RB
Series C, 4.00%, 02/15/41	$	6,497	$	7,248,001
Series C, 4.00%, 02/15/41^(e)		13		14,019
Illinois State Toll Highway Authority, RB, Series A, 5.00%, 01/01/40		5,011		5,758,731


				15,551,021

Maryland — 1.0%
Maryland Health & Higher Educational Facilities Authority, RB, Series B, 4.00%, 04/15/50		15,000		17,024,100


Massachusetts — 0.2%
Commonwealth of Massachusetts Transportation Fund Revenue, RB, Series A, 4.00%, 06/01/45		3,464		3,810,702


New York — 6.9%
Hudson Yards Infrastructure Corp., RB, 5.75%, 02/15/47^(j)		643		646,727
New York City Housing Development Corp., RB, M/F Housing
Series C-1A, 4.15%, 11/01/39		3,107		3,244,440
Series C-1A, 4.20%, 11/01/44		5,695		5,946,945
Series C-1A, 4.30%, 11/01/47		4,660		4,866,590
New York City Water & Sewer System, Refunding RB, Series HH, 5.00%, 06/15/31^(j)		3,015		3,043,944
New York Liberty Development Corp., ARB, 5.25%, 12/15/43		7,725		7,974,989
New York Liberty Development Corp., Refunding RB, 5.75%, 11/15/51^(j)		2,520		2,591,482
New York Power Authority, Refunding RB, Series A, 4.00%, 11/15/60		3,421		3,906,111
New York State Dormitory Authority, Refunding RB
Series D, 4.00%, 02/15/47		17,080		19,512,192
Series E, 5.00%, 03/15/36		21,670		25,544,813
New York State Urban Development Corp., RB, Series A, 4.00%, 03/15/46.		13,005		14,528,926
Port Authority of New York & New Jersey, ARB, Series 221, AMT, 4.00%, 07/15/60		16,595		18,455,297
Port Authority of New York & New Jersey, Refunding ARB, 194th Series, 5.25%, 10/15/55		2,925		3,413,651


				113,676,107

North Carolina — 0.2%
North Carolina Capital Facilities Finance Agency, Refunding RB, Series B, 5.00%, 10/01/25^(e)		2,930		3,518,959


Pennsylvania — 1.0%
Pennsylvania Economic Development Financing Authority, RB, Series A-1, 4.00%, 04/15/50		11,000		12,481,260
Pennsylvania Turnpike Commission, RB, Sub- Series A, 5.50%, 12/01/42		3,677		4,479,744


				16,961,004

Rhode Island — 0.2%
Narragansett Bay Commission, Refunding RB, Series A, 4.00%, 09/01/22^(e)		2,641		2,782,143


Texas — 0.2%
Lower Colorado River Authority, Refunding, RB, 4.00%, 05/15/43		3,480		3,610,604


S C H E D U L E O F I N V E S T M E N T S		11

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

(Percentages shown are based on Net Assets)


Security	Par (000)		Value


Virginia — 0.5%
Hampton Roads Transportation Accountability Commission, RB, Series A, Senior Lien, 4.00%, 07/01/60^(j)	$	6,249	$	7,170,421


Washington — 0.8%
City of Bellingham Washington Water & Sewer Revenue, RB, 5.00%, 08/01/40		2,998		3,045,921
Snohomish County Public Utility District No. 1, RB, 5.00%, 12/01/45		8,664		10,068,737


				13,114,658

Wisconsin — 0.1%
Wisconsin Health & Educational Facilities Authority, Refunding RB, 4.00%, 12/01/46		1,774		1,954,859


Total Municipal Bonds Transferred to Tender Option Bond Trusts — 12.3% (Cost: $190,150,062)				202,668,958


Total Long-Term Investments — 102.5% (Cost: $1,551,746,846)				1,686,930,712

^(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)	Step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate as of period end.

^(d)	Zero-coupon bond.

^(e)	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.

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

^(g)	Non-income producing security.

^(h)	When-issued 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 May 15, 2021 to February 15, 2047, is $8,056,364.

^(k)	Affiliate of the Fund.

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


	Shares


Short-Term Securities

Money Market Funds — 4.0%
BlackRock Liquidity Funds, MuniCash, Institutional Class, 0.01%^(k)(l)		65,298,955		65,312,014


Total Short-Term Securities — 4.0% (Cost: $65,311,594)				65,312,014


Total Investments — 106.5% (Cost: $1,617,058,440)				1,752,242,726

Other Assets Less Liabilities — 0.6%				10,261,388

Liability for TOB Trust Certificates, Including Interest Expense and Fees Payable — (7.1)%				(116,916,252	)


Net Assets — 100.0%			$	1,645,587,862

Affiliates

Investments in issuers considered to be affiliate(s) of the Fund during the period ended March 31, 2021 for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:




Affiliated Issuer	Value at 06/30/20		Purchases at Cost		Proceeds from Sales			Net Realized Gain (Loss)		Change in Unrealized Appreciation (Depreciation)			Value at 03/31/21		Shares Held at 03/31/21		Income		Capital Gain Distributions from Underlying Funds

BlackRock Liquidity Funds, MuniCash, Institutional Class	$	93,924,405	$	—		$ (28,611,200	)^(a)	$	2,108	$	(3,299	)	$	65,312,014		65,298,955	$	8,043	$	—

^(a)

Represents net amount purchased (sold).


12

Schedule of Investments (unaudited) (continued)

March 31, 2021

BlackRock High Yield Municipal Fund

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 investments categorized in the fair value hierarchy. The breakdown of the Fund’s investments into major categories is disclosed in the Schedule of Investments above.




	Level 1		Level 2		Level 3		Total

Assets
Investments
Long-Term Investments
Municipal Bonds	$	—	$	1,484,261,754	$	—	$	1,484,261,754
Municipal Bonds Transferred to Tender Option Bond Trusts		—		202,668,958		—		202,668,958
Short-Term Securities Money Market Funds		65,312,014		—		—		65,312,014

	$	65,312,014	$	1,686,930,712	$	—	$	1,752,242,726

The Fund may hold assets and/or liabilities in which the fair value approximates the carrying amount for financial statement purposes. As of period end, TOB Trust Certificates of $116,876,627 are categorized as Level 2 within the fair value hierarchy.


Portfolio Abbreviation

AGC		Assured Guaranty Corp.

AGM		Assured Guaranty Municipal Corp.

AMT		Alternative Minimum Tax

ARB		Airport Revenue Bonds

CAB		Capital Appreciation Bonds

CBI		Certificate of Beneficial Interest

GO		General Obligation Bonds

GTD		GTD Guaranteed

M/F		Multi-Family

NPFGC		National Public Finance Guarantee Corp.

RB		Revenue Bond

S/F		Single-Family

SAB		Special Assessment Bonds

SONYMA		State of New York Mortgage Agency

ST		Special Tax


Portfolio Abbreviation (continued)

TA		Tax Allocation


S C H E D U L E O F I N V E S T M E N T S		13

Blackrock Municipal Bond Fund NPORT-PBlackRock High Yield Municipal Fund (Mar 2021 report)