Blackrock Muniholdings Investment Quality Fund (MFL) NPORT-P BlackRock MuniHoldings Investment Quality Fund (Nov 2021 report)

Schedule of Investments  (unaudited) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL) (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Municipal Bonds
Alabama — 1.4%
Black Belt Energy Gas District, Refunding RB, 4.00%, 06/01/51(a)	$	5,010	$	6,114,695
Selma Industrial Development Board, RB, Series A, 5.38%, 12/01/35		1,745		1,751,408
				7,866,103
Arizona — 4.4%
Arizona Industrial Development Authority, RB(b) 4.38%, 07/01/39		1,015		1,109,770
Series A, 5.00%, 07/01/39		855		902,553
Series A, 5.00%, 07/01/49		965		1,011,210
Series A, 5.00%, 07/01/54		745		779,573
Industrial Development Authority of the County of Pima, RB, 5.00%, 06/15/47(b)		1,480		1,499,074
Industrial Development Authority of the County of Pima, Refunding RB, 5.00%, 06/15/52(b)		825		875,834
Maricopa County Industrial Development Authority, Refunding RB 5.00%, 07/01/39(b)		360		422,587
5.00%, 07/01/54(b)		820		939,065
Series A, 5.00%, 01/01/38		3,000		3,584,781
Salt River Project Agricultural Improvement & Power District, RB, 4.00%, 01/01/41		10,000		11,917,670
University of Arizona, Refunding RB, Series A, 5.00%, 06/01/40		2,300		2,624,245
				25,666,362
Arkansas — 0.4%
Arkansas Development Finance Authority, RB, Series A, AMT, 4.50%, 09/01/49(b)		2,395		2,644,643
California — 13.5%
California Community Choice Financing Authority RB, Series B-1, 4.00%, 02/01/52(a)		2,000		2,425,542
California Community Housing Agency, RB, M/F Housing(b)
Series A, 5.00%, 04/01/49		370		419,455
Series A-2, 4.00%, 08/01/47		2,380		2,469,883
California State Public Works Board, RB
Series F, 5.25%, 09/01/33		3,240		3,509,455
Series I, 5.50%, 11/01/30		4,500		4,938,309
Series I, 5.50%, 11/01/33		2,000		2,192,208
California State University, Refunding RB, Series A, 5.00%, 11/01/42		3,500		4,254,096
City of Los Angeles Department of Airports Refunding RB, Series D, AMT, 4.00%, 05/15/51		2,000		2,337,940
Golden State Tobacco Securitization Corp., Refunding RB
Series A-1, 5.00%, 06/01/47		2,880		2,930,285
Series A-2, 5.00%, 06/01/47		785		798,859
Los Angeles County Metropolitan Transportation Authority RB, 4.00%, 06/01/37		7,550		9,346,583
Manteca Financing Authority, RB, Series A, (AGC-ICC), 5.75%, 12/01/36		3,285		3,298,928
Regents of the University of California Medical Center Pooled Revenue, Refunding RB, Series J, 5.25%, 05/15/38		2,705		2,888,691

Security	Par (000)		Value
California (continued)
San Francisco City & County Airport Comm-San Francisco International Airport, Refunding ARB
Series A, AMT, 5.25%, 05/01/33	$	6,370	$	6,788,490
Series A, AMT, 5.00%, 05/01/38		3,040		3,782,803
Series A, AMT, 5.00%, 05/01/44		3,430		3,757,170
Series B, AMT, 5.00%, 05/01/46		7,855		9,320,829
University of California, Refunding RB, Series AR, 5.00%, 05/15/38		10,200		12,094,303
				77,553,829
Colorado — 3.2%
City & County of Denver Colorado Airport System Revenue, ARB
Series A, AMT, 5.50%, 11/15/28		2,700		2,955,326
Series A, AMT, 5.50%, 11/15/30		1,040		1,137,380
Series A, AMT, 5.50%, 11/15/31		1,250		1,366,305
City & County of Denver Colorado Airport System Revenue, Refunding ARB, Series A, AMT, 5.00%, 12/01/43		10,500		12,815,376
				18,274,387
Connecticut — 0.1%
Connecticut State Health & Educational Facilities Authority, RB, Series A-1, 5.00%, 10/01/54(b)		235		258,087
State of Connecticut, Special Tax Revenue, RB, Series D, 4.00%, 11/01/40(c)		250		303,304
				561,391
District of Columbia — 1.3%
Metropolitan Washington Airports Authority, Refunding RB, Series A, AMT, 4.00%, 10/01/38		3,000		3,525,393
Washington Metropolitan Area Transit Authority, RB, 5.00%, 07/15/46		3,220		4,172,782
				7,698,175
Florida — 4.0%
Capital Trust Agency, Inc., RB(b)
Series A, 5.00%, 06/01/45		850		905,749
Series SE, 3.00%, 07/01/31		125		129,917
Series SE, 4.00%, 07/01/41		285		313,606
Series SE, 4.00%, 07/01/51		335		362,368
Series SE, 4.00%, 07/01/56		280		301,893
County of Miami-Dade Seaport Department, ARB(d)
Series A, 5.38%, 10/01/23		3,145		3,437,557
Series B, AMT, 6.00%, 10/01/23		1,885		2,081,770
Series B, AMT, 6.25%, 10/01/23		1,405		1,555,935
Esplanade Lake Club Community Development District, SAB
Series A-1, 4.00%, 11/01/40		1,080		1,134,546
Series A-1, 4.13%, 11/01/50		385		403,294
Series A-2, 4.00%, 11/01/40		500		525,253
Series A-2, 4.13%, 11/01/50		495		518,521
Florida Development Finance Corp., RB(b) AMT, 5.00%, 05/01/29		825		877,443
Series A, AMT, 5.00%, 08/01/29(a)		325		332,859
Florida Development Finance Corp., Refunding RB, Series C, 5.00%, 09/15/50(b)		475		522,418
Hillsborough County Aviation Authority, Refunding RB
Series A, AMT, 5.25%, 10/01/30		3,255		3,534,608

1

Schedule of Investments  (unaudited) (continued) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL) (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Florida (continued)
Hillsborough County Aviation Authority, Refunding RB (continued)
Sub-Series A, AMT, 5.50%, 10/01/29	$	5,360	$	5,846,940
Lee County Housing Finance Authority, RB, S/F Housing, Series A-2, AMT, (GNMA/FNMA/FHLMC), 6.00%, 09/01/40		200		200,712
				22,985,389
Hawaii — 1.9%
State of Hawaii Airports System Revenue, ARB,
Series A, AMT, 5.00%, 07/01/45		5,985		6,764,528
State of Hawaii Airports System Revenue, COP AMT, 5.25%, 08/01/25		1,350		1,454,054
AMT, 5.25%, 08/01/26		2,500		2,692,003
				10,910,585
Idaho — 2.0%
Idaho Health Facilities Authority, RB, 4.00%, 12/01/43		10,000		11,721,390
Illinois — 16.2%
Chicago Board of Education, GO
Series A, 5.00%, 12/01/36		1,760		2,212,248
Series A, 5.00%, 12/01/38		715		895,146
Series A, 5.00%, 12/01/39		630		786,927
Series A, 5.00%, 12/01/40		1,285		1,601,127
Series A, 5.00%, 12/01/41		835		1,039,009
Chicago Board of Education, Refunding GO
Series A, 5.00%, 12/01/28		365		449,195
Series A, 5.00%, 12/01/30		1,485		1,857,667
Chicago Board of Education, Refunding GO, CAB, Series A, 0.00%, 12/01/25(e)		395		376,477
Chicago Midway International Airport, Refunding ARB, Series A, 2nd Lien, AMT, 5.00%, 01/01/41		8,020		8,663,404
Chicago Midway International Airport, Refunding RB
Series A, 2nd Lien, AMT, 5.50%, 01/01/30		6,500		6,834,841
Series A, 2nd Lien, AMT, 5.50%, 01/01/32		6,275		6,594,931
Chicago O’Hare International Airport, ARB, Series D, Senior Lien, 5.25%, 01/01/42.		2,630		3,143,313
Chicago O’Hare International Airport, Refunding RB
Series B, Senior Lien, 5.00%, 01/01/35		4,300		5,132,157
Series C, Senior Lien, 4.00%, 01/01/37		4,000		4,699,204
Series C, Senior Lien, 4.00%, 01/01/38		3,820		4,434,879
Series E, Senior Lien, (AGM), 4.00%, 01/01/39		5,000		5,906,010
Chicago Transit Authority Sales Tax Receipts Fund, RB, 5.25%, 12/01/21(d)		10,960		10,960,000
Illinois State Toll Highway Authority, RB, Series A, 5.00%, 01/01/40		5,000		5,708,160
State of Illinois, GO 5.50%, 05/01/39		15,000		19,270,470
5.75%, 05/01/45		2,000		2,564,328
				93,129,493
Indiana — 0.5%
Indiana Finance Authority, RB
Series A, 5.00%, 06/01/41		550		618,717
Series A, 5.00%, 06/01/51		405		446,928
Series A, 5.00%, 06/01/56		360		395,601
Series A, AMT, 5.00%, 07/01/23(d)		1,240		1,331,073
				2,792,319

Security	Par (000)		Value
Massachusetts — 6.8%
Commonwealth of Massachusetts, GO, Series G, 4.00%, 09/01/42	$	20,000	$	22,689,720
Massachusetts Development Finance Agency, Refunding RB, 5.00%, 07/01/41		4,710		5,537,053
Massachusetts Educational Financing Authority, RB,
AMT, 5.00%, 01/01/27		1,000		1,115,705
Massachusetts Housing Finance Agency, Refunding RB, M/F Housing, Series G, 3.45%, 12/01/30		3,100		3,325,268
Massachusetts School Building Authority, RB, Sub- Series B, 4.00%, 02/15/42		6,200		6,652,581
				39,320,327
Michigan — 2.0%
City of Detroit Michigan Water Supply System Revenue, RB, Series B, 2nd Lien, (AGM), 6.25%, 07/01/36		10		10,044
Michigan Finance Authority, RB, 4.00%, 02/15/44		10,000		11,600,220
				11,610,264
Mississippi — 2.4%
Mississippi Development Bank, RB
(AGM), 6.75%, 12/01/31		3,775		4,202,039
(AGM), 6.75%, 12/01/33		2,350		2,612,420
(AGM), 6.88%, 12/01/40		6,405		7,120,214
				13,934,673
Missouri — 0.5%
Health & Educational Facilities Authority of the State of Missouri, Refunding RB, Series A, 4.00%, 07/01/46		2,275		2,686,097
New Jersey — 14.5%
New Jersey Economic Development Authority, RB
AMT, (AGM), 5.00%, 01/01/31		2,425		2,636,227
AMT, 5.38%, 01/01/43		7,000		7,632,072
New Jersey Economic Development Authority, Refunding RB, Series BBB, 5.50%, 06/15/30		4,080		4,947,183
New Jersey Higher Education Student Assistance Authority, Refunding RB, 1st Series, AMT, 5.75%, 12/01/28		1,450		1,451,953
New Jersey Transportation Trust Fund Authority, RB
Series AA, 5.50%, 06/15/39		8,175		8,751,207
Series AA, 4.00%, 06/15/40		4,000		4,636,544
Series BB, 5.00%, 06/15/44		5,000		6,084,795
Series S, 5.25%, 06/15/43		10,000		12,456,180
New Jersey Turnpike Authority, RB, Series A, 4.00%, 01/01/42		2,500		2,961,625
New Jersey Turnpike Authority, Refunding RB, Series A, 5.00%, 01/01/34		1,685		1,959,534
State of New Jersey GO, 2.00%, 06/01/34		12,505		12,456,881
Tobacco Settlement Financing Corp., Refunding RB,
Sub-Series B, 5.00%, 06/01/46		15,000		17,511,105
				83,485,306
New Mexico — 0.1%
City of Santa Fe New Mexico, RB, Series A, 5.00%, 05/15/39		310		347,896
New York — 15.4%
Metropolitan Transportation Authority, RB
Series A-1, 5.25%, 11/15/39		7,005		7,527,601
Series C, 5.00%, 11/15/38		4,450		4,705,826
New York City Transitional Finance Authority Future Tax Secured Revenue, RB, Series C-3, Subordinate, 4.00%, 05/01/43		5,000		5,761,485

SCHEDULE   OF   INVESTMENTS 2

Schedule of Investments  (unaudited) (continued) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL) (Percentages shown are based on Net Assets)

Security	Par (000)		Value
New York (continued)
New York City Water & Sewer System, RB,
Series CC-1, Subordinate, 5.00%, 06/15/51	$	5,385	$	6,930,920
New York Convention Center Development Corp., RB, CAB, Series B, Sub-Lien, (BAM-TCRS), 0.00%, 11/15/40(e)		7,000		4,403,602
New York Liberty Development Corp., Refunding RB 2.88%, 11/15/46		12,000		12,222,564
Series 1, Class 1, 5.00%, 11/15/44(b)		1,730		1,893,174
New York Power Authority, Refunding RB, Series A, 4.00%, 11/15/55		10,135		11,821,038
New York State Thruway Authority, Refunding RB,
Series A-1, 4.00%, 03/15/44		2,460		2,912,182
New York State Urban Development Corp. RB, Series A, 3.00%, 03/15/40		11,920		12,885,806
New York Transportation Development Corp., RB
AMT, 5.00%, 10/01/35		630		781,147
AMT, 5.00%, 10/01/40		1,775		2,166,098
Triborough Bridge & Tunnel Authority, RB, Series C- 2, 4.00%, 05/15/46		4,500		5,374,071
Triborough Bridge & Tunnel Authority, Refunding RB 4.00%, 05/15/46		3,250		3,834,308
Series B, 5.00%, 11/15/38		4,400		5,314,351
				88,534,173
Ohio — 4.3%
Buckeye Tobacco Settlement Financing Authority, Refunding RB, Series B-2, Class 2, 5.00%, 06/01/55		8,490		9,720,965
Ohio Turnpike & Infrastructure Commission, RB
Series A-1, Junior Lien, 5.25%, 02/15/31		5,145		5,438,471
Series A-1, Junior Lien, 5.25%, 02/15/32		2,250		2,377,764
State of Ohio, RB, 4.00%, 01/01/41		6,000		6,977,640
State of Ohio, Refunding RB, Series A, 4.00%, 01/01/28(d)		25		29,706
				24,544,546
Pennsylvania — 5.6%
Bristol Township School District, GO, (SAW), 5.25%, 06/01/23(d)		3,000		3,209,895
Bucks County Industrial Development Authority, RB 4.00%, 07/01/46		145		162,938
4.00%, 07/01/51		100		111,849
Pennsylvania Turnpike Commission, RB
Series A, 5.25%, 12/01/44		5,000		6,295,660
Sub-Series A, 5.50%, 12/01/46		18,570		22,679,244
			32,459,586
Puerto Rico — 4.7%
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB
Series A-1, Restructured, 4.75%, 07/01/53		719		819,911
Series A-1, Restructured, 5.00%, 07/01/58		6,203		7,130,286
Series A-2, Restructured, 4.33%, 07/01/40		12,484		14,038,633
Series A-2, Restructured, 4.78%, 07/01/58		488		556,958
Series B-1, Restructured, 4.75%, 07/01/53		749		852,489
Series B-2, Restructured, 4.78%, 07/01/58		726		825,448
Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue, RB, CAB, Series A-1, Restructured, 0.00%, 07/01/46(e)		8,018		2,676,649
				26,900,374

Security	Par (000)		Value
South Carolina — 5.4%
Charleston County Airport District, ARB
Series A, AMT, 5.25%, 07/01/25	$	4,490	$	4,830,769
Series A, AMT, 5.50%, 07/01/38		3,000		3,224,487
Series A, AMT, 6.00%, 07/01/38		5,270		5,705,676
Series A, AMT, 5.50%, 07/01/41		4,170		4,475,382
County of Charleston South Carolina, ARB, 5.25%, 12/01/23(d)		6,735		7,401,502
South Carolina Jobs-Economic Development Authority, Refunding RB, Series A, 5.00%, 05/01/37		4,480		5,417,359
				31,055,175
Texas — 10.9%
City of Dallas TX Waterworks & Sewer System Revenue Refunding RB, Series C, 3.00%, 10/01/46		5,110		5,607,489
City of Houston Texas Airport System Revenue, RB, Series A, AMT, 6.63%, 07/15/38		700		703,129
City of Houston Texas Airport System Revenue, Refunding ARB, AMT, 5.00%, 07/15/27		410		475,589
City of Houston Texas Airport System Revenue, Refunding RB, Series A, AMT, 5.00%, 07/01/27		400		462,945
Lower Colorado River Authority, Refunding RB, 5.50%, 05/15/33		3,735		3,992,655
New Hope Cultural Education Facilities Finance Corp., RB, Series A, 5.00%, 08/15/50(b)		800		857,118
Red River Education Finance Corp., RB, 5.25%, 03/15/23(d)		7,170		7,631,949
San Antonio Water System, Refunding RB, Series A, 5.00%, 05/15/46		10,000		12,932,520
State of Texas, GO, 5.00%, 04/01/43		15,550		18,142,278
Texas City Industrial Development Corp., RB,
Series 2012, 4.13%, 12/01/45		445		478,003
Texas Water Development Board, RB 5.25%, 10/15/46		4,780		5,732,248
Series B, 4.00%, 10/15/43		5,000		5,878,150
				62,894,073
Utah — 2.4%
County of Utah, RB, Series B, 5.00%, 05/15/46		8,590		10,031,539
Utah Charter School Finance Authority, RB, Series A, 5.00%, 06/15/49(b)		320		340,689
Utah State University, RB, Series B, (AGM), 4.00%, 12/01/45		3,000		3,476,343
				13,848,571
Washington — 0.5%
State of Washington, GO, Series C, 5.00%, 02/01/41		2,500		3,074,168
Wisconsin(b) — 1.0%
Public Finance Authority RB, 5.00%, 06/15/56		1,000		1,029,223
Public Finance Authority, RB
Series A, 5.00%, 07/15/39		165		185,784
Series A, 5.00%, 07/15/49		630		698,487
Series A, 5.00%, 10/15/50		1,695		1,852,386
Series A, 5.00%, 07/15/54		300		331,496
Series A-1, 5.00%, 01/01/55		945		1,050,450
Public Finance Authority, Refunding RB, 5.00%, 09/01/49		520		560,889
				5,708,715
Total Municipal Bonds — 125.4%     (Cost: $671,876,281)			722,208,010

3

Schedule of Investments  (unaudited) (continued) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL) (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Municipal Bonds Transferred to Tender Option Bond Trusts(f)
Alabama — 8.0%
Alabama Special Care Facilities Financing Authority- Birmingham AL, Refunding RB, Series B, 5.00%, 11/15/46	$	39,718	$	46,106,019
District of Columbia — 3.0%
Washington Dc Met Area Transit, 4.00%, 07/15/45		15,000		17,523,758
Massachusetts — 4.4%
Commonwealth of Massachusetts, GO, Series E, 5.25%, 09/01/43		20,000		25,420,920
Michigan — 2.0%
Michigan Finance Authority, Refunding RB, Series A, 4.00%, 12/01/40		10,100		11,571,030
Nevada — 2.0%
County of Clark Nevada, GO, 4.00%, 07/01/47		10,000		11,273,975
New York — 15.0%
Hudson Yards Infrastructure Corp, Refunding RB, Series A, 4.00%, 02/15/44		30,165		34,157,075
New York City Transitional Finance Authority Building Aid Revenue, RB, Series S-1, 5.00%, 07/15/43		11,825		14,594,621
New York City Transitional Finance Authority Future Tax
Secured Revenue, RB, Sub-Series B-1, 4.00%, 11/01/41		20,000		23,540,270
New York Liberty Development Corp., ARB, 5.25%, 12/15/43		13,950		13,974,487
				86,266,453
Pennsylvania — 1.9%
Geisinger Authority, Refunding RB, Series A, 4.00%, 06/01/41		10,000		10,754,985
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 36.3% (Cost: $195,259,629)				208,917,140
Total Long-Term Investments — 161.7% (Cost: $867,135,910)				931,125,150

Security	Shares		Value
Short-Term Securities
Money Market Funds — 0.4%
BlackRock Liquidity Funds, MuniCash, Institutional Class, 0.01%(g)(h)		2,091,004	$	2,091,213
Total Short-Term Securities — 0.4% (Cost: $2,091,213)				2,091,213
Total Investments — 162.1% (Cost: $869,227,123)				933,216,363
Other Assets Less Liabilities — 1.6%				9,424,793
Liability for TOB Trust Certificates, Including Interest Expense and Fees Payable — (16.1)%				(92,725,458	)
VRDP Shares at Liquidation Value, Net of Deferred Offering Costs — (47.6)%				(274,269,201	)
Net Assets Applicable to Common Shares — 100.0%			$	575,646,497

^(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) When-issued security.

^(d) 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.

^(e) Zero-coupon bond.

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

^(g) Affiliate of the Trust.

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

Affiliates

Investments in issuers considered to be affiliate(s) of the Trust during the period ended November 30, 2021 for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliated Issuer	Value at 08/31/21		Purchases at Cost		Proceeds from Sales			Net Realized Gain (Loss)			Change in Unrealized Appreciation (Depreciation)		Value at 11/30/21		Shares Held at 11/30/21		Income		Capital Gain Distributions from Underlying Funds
BlackRock Liquidity Funds, MuniCash, Institutional Class	$	16,431,699	$	—	$	(14,339,817	)(a)	$	(669	)	$	—	$	2,091,213		2,091,004	$	110	$	—

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

SCHEDULE   OF   INVESTMENTS 4

Schedule of Investments  (unaudited) (continued) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL)

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Short Contracts
10-Year U.S. Treasury Note		327		03/22/22	$	42,765	$	(444,506	)
U.S. Long Bond		169		03/22/22		27,410		(552,545	)
5-Year U.S. Treasury Note		235		03/31/22		28,521		(173,823	)
							$	(1,170,874	)

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 Trust 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 Trust’s policy regarding valuation of financial instruments, refer to its most recent financial statements.

The following table summarizes the Trust’s financial instruments categorized in the fair value hierarchy. The breakdown of the Trust’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
Municipal Bonds	$	—		$	722,208,010	$	—	$	722,208,010
Municipal Bonds Transferred to Tender Option Bond Trusts		—			208,917,140		—		208,917,140
Short-Term Securities
Money Market Funds		2,091,213			—		—		2,091,213
									��
	$	2,091,213		$	931,125,150	$	—	$	933,216,363
Derivative Financial Instruments(a)
Liabilities
Interest Rate Contracts	$	(1,170,874	)	$	—	$	—	$	(1,170,874)

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

5

Schedule of Investments  (unaudited) (continued) November 30, 2021 BlackRock MuniHoldings Investment Quality Fund (MFL)

The Trust may hold assets and/or liabilities in which the fair value approximates the carrying amount for financial reporting purposes. As of period end, such assets and/or liabilities are categorized within the fair value hierarchy as follows:

	Level 1		Level 2			Level 3		Total
Liabilities
TOB Trust Certificates	$	—	$	(92,712,729	)	$	—	$	(92,712,729	)
VRDP Shares at Liquidation Value		—		(274,600,000	)		—		(274,600,000	)
	$	—	$	(367,312,729	)	$	—	$	(367,312,729	)

Portfolio Abbreviation
AGC-ICC	Assured Guaranty Corp. – Insured Custody Certificate
AGM	Assured Guaranty Municipal Corp.
AMT	Alternative Minimum Tax
ARB	Airport Revenue Bonds
BAM-TCRS	Build America Mutual Assurance Co.- Transferable Custodial Receipts
CAB	Capital Appreciation Bonds
COP	Certificates of Participation
GO	General Obligation Bonds
M/F	Multi-Family
RB	Revenue Bond
S/F	Single-Family
SAB	Special Assessment Bonds
SAW	State Aid Withholding

SCHEDULE   OF   INVESTMENTS 6