mft.htm - Produced by Pellegrini and Associates, Inc. | 134 Spring Street New York NY 10012 | (212) 925-5151

UNITEDSTATES
SECURITIESANDEXCHANGECOMMISSION
Washington,D.C.20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number 811-07156

Name of Fund: BlackRock MuniYield Investment Quality Fund (MFT)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Anne F. Ackerley, Chief Executive Officer, BlackRock
MuniYield Investment Quality Fund, 55 East 52nd Street, New York, NY 10055

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 07/31/2011

Date of reporting period: 10/31/2010

Item 1 – Schedule of Investments


Schedule of Investments October 31, 2010 (Unaudited)

BlackRock MuniYield Investment Quality Fund (MFT)
(Percentages shown are based on Net Assets)

    Par   
Municipal Bonds    (000)  Value 
Alabama — 4.1%       
Birmingham Special Care Facilities       
Financing Authority, RB, Children's       
Hospital (AGC):       
6.13%, 6/01/34  $ 1,500  $ 1,668,600 
6.00%, 6/01/39    2,985  3,277,739 
      4,946,339 
Arizona — 0.5%       
State of Arizona, COP, Department of     
Administration, Series A (AGM):       
5.25%, 10/01/28    480  508,008 
5.00%, 10/01/29    125  129,175 
      637,183 
California — 15.1%       
California State Public Works Board, RB,     
Various Capital Projects, Series G-1     
(AGC), 5.25%, 10/01/24    2,000  2,184,420 
California State University, RB,       
Systemwide, Series A (AGM), 5.00%,     
11/01/39    1,000  1,030,900 
County of Sacramento California, RB,     
Senior Series A (AGC), 5.50%,       
7/01/41    1,400  1,489,894 
Los Angeles Community College District     
California, GO, Election of 2001,       
Series A (NPFGC), 5.00%, 8/01/32  2,780  2,912,801 
Oxnard Union High School District, GO,     
Refunding, Election of 2004, Series A     
(AGM), 5.00%, 8/01/40    1,500  1,550,205 
San Diego Public Facilities Financing       
Authority, Refunding RB, Series B       
(AGC), 5.38%, 8/01/34    1,020  1,108,536 
San Jacinto Unified School District, GO,     
Election of 2006 (AGM), 5.25%,       
8/01/32    1,000  1,051,530 
State of California, GO, Various Purpose:     
(AGC), 5.50%, 11/01/39    3,450  3,648,168 
(AGM), 5.00%, 6/01/32    3,000  3,063,990 
      18,040,444 
Colorado — 1.2%       
Colorado Health Facilities Authority, RB,     
Hospital, NCMC Inc. Project, Series B     
(AGM), 6.00%, 5/15/26    1,300  1,477,515 

 

    Par   
Municipal Bonds    (000)  Value 
Florida — 18.7%       
County of Lee Florida, RB, Series A,       
AMT (AGM), 6.00%, 10/01/29  $ 1,000  $ 1,011,240 
County of Miami-Dade Florida, RB,       
Miami International Airport, Series A,     
AMT (AGM), 5.50%, 10/01/41    2,400  2,471,280 
County of Osceola Florida, RB, Series A     
(NPFGC), 5.50%, 10/01/27    1,100  1,126,312 
County of St. John's Florida, RB (AGM),     
5.00%, 10/01/31    2,135  2,234,000 
Florida Housing Finance Corp., HRB,       
Brittany Rosemont Apartments, Series     
C-1, AMT (AMBAC), 6.75%, 8/01/14  640  641,030 
Florida Housing Finance Corp., RB,       
Homeowner Mortgage, Series 11,       
AMT (AGM), 5.95%, 1/01/32    1,415  1,416,245 
Florida Housing Finance Corp.,       
Refunding RB, Homeowner Mortgage,     
Series 4, AMT (AGM), 6.25%,       
7/01/22    215  228,119 
Jacksonville Economic Development       
Commission, RB, Mayo Clinic, Series B     
(NPFGC), 5.50%, 11/15/36    750  766,410 
Palm Beach County School District, COP,     
Refunding, Series D (AGM), 5.25%,     
8/01/21    1,925  2,037,863 
Santa Rosa County School Board, COP,     
Refunding, Series 2 (NPFGC), 5.25%,     
2/01/26    2,000  2,122,180 
South Broward Hospital District, RB,       
Hospital (NPFGC), 5.63%, 5/01/12 (a)  4,000  4,342,800 
St. Lucie West Services District, RB       
(NPFGC), 5.25%, 10/01/34    1,000  1,024,760 
Village Center Community Development     
District, RB, Series A (NPFGC):       
5.38%, 11/01/34    1,640  1,542,207 
5.13%, 11/01/36    1,000  901,880 
Volusia County IDA, RB, Student       
Housing, Stetson University Project,     
Series A (CIFG), 5.00%, 6/01/35    525  477,330 
      22,343,656 
Georgia — 4.7%       
County of Fulton Georgia, RB (NPFGC),     
5.25%, 1/01/35    1,000  1,071,350 

 

Portfolio Abbreviations

To simplify the listings of portfolio holdings in the Schedule of Investments, the names and descriptions of many of the securities have been abbreviated
according to the following list:

AGC  Assured Guaranty Corp.  GARB  General Airport Revenue Bonds 
AGM  Assured Guaranty Municipal Corp.  GO  General Obligation Bonds 
AMBAC  American Municipal Bond Assurance Corp.  HRB  Housing Revenue Bonds 
AMT  Alternative Minimum Tax (subject to)  IDA  Industrial Development Authority 
BHAC  Berkshire Hathaway Assurance Corp.  ISD  Independent School District 
CIFG  CDC IXIS Financial Guaranty  NPFGC  National Public Finance Guarantee Corp. 
COP  Certificates of Participation  RB  Revenue Bonds 
EDA  Economic Development Authority  S/F  Single Family 
ERB  Education Revenue Bonds     

 

BLACKROCK MUNIYIELD INVESTMENT QUALITY FUND

OCTOBER 31, 2010

1


Schedule of Investments(continued)

BlackRock MuniYield Investment Quality Fund (MFT)
(Percentages shown are based on Net Assets)

  Par   
Municipal Bonds  (000)  Value 
Georgia (concluded)     
Georgia Higher Education Facilities     
Authority, RB, USG Real Estate III,     
Series A (AGC), 5.00%, 6/15/38  $ 870  $ 894,047 
Gwinnett County Hospital Authority,     
Refunding RB, Gwinnett Hospital     
System, Series D (AGM), 5.50%,     
7/01/41  1,375  1,429,656 
Metropolitan Atlanta Rapid Transit     
Authority, RB, Third Indenture, Series     
B (AGM), 5.00%, 7/01/34  2,100  2,229,381 
    5,624,434 
Illinois — 12.2%     
Chicago Board of Education Illinois, GO,     
Refunding, Chicago School Reform     
Board, Series A (NPFGC), 5.50%,     
12/01/26  825  954,187 
Chicago Transit Authority, RB, Federal     
Transit Administration Section 5309,     
Series A (AGC), 6.00%, 6/01/26  1,400  1,633,926 
City of Chicago Illinois, GO, Refunding,     
Projects, Series A (AGM):     
5.00%, 1/01/28  945  1,008,674 
5.00%, 1/01/29  1,465  1,553,369 
5.00%, 1/01/30  585  617,093 
City of Chicago Illinois, RB, General,     
Third Lien, Series C (AGM), 5.25%,     
1/01/35  835  876,458 
City of Chicago Illinois, Refunding RB,     
Second Lien (NPFGC), 5.50%,     
1/01/30  895  1,012,469 
Illinois Municipal Electric Agency, RB,     
Series A (NPFGC):     
5.25%, 2/01/28  1,565  1,655,363 
5.25%, 2/01/35  1,250  1,295,012 
State of Illinois, RB:     
(AGM), 5.00%, 6/15/27  1,000  1,037,110 
Build Illinois, Series B, 5.25%,     
6/15/28  1,750  1,889,632 
Village of Schaumburg Illinois, GO,     
Series B (NPFGC), 5.00%, 12/01/38  1,000  1,021,070 
    14,554,363 
Indiana — 4.3%     
Indiana Municipal Power Agency, RB,     
Series A (NPFGC), 5.00%, 1/01/42  1,485  1,513,319 
Indianapolis Local Public Improvement     
Bond Bank, Refunding RB,     
Waterworks Project, Series A (AGC),     
5.50%, 1/01/38  3,310  3,636,068 
    5,149,387 
Iowa — 1.1%     
Iowa Finance Authority, Refunding RB,     
Iowa Health System (AGC), 5.25%,     
2/15/29  1,190  1,281,856 
Kentucky — 1.1%     
Kentucky Municipal Power Agency, RB,     
Prairie State Project, Series A (BHAC),     
5.25%, 9/01/42  1,250  1,308,325 

 

    Par   
Municipal Bonds    (000)  Value 
Louisiana — 1.8%       
Louisiana State Citizens Property       
Insurance Corp., RB, Series C-3 (AGC),     
6.13%, 6/01/25  $ 1,405  $ 1,581,960 
New Orleans Aviation Board Louisiana,     
Refunding RB (AGC), Restructuring     
GARB:       
Series A-1, 6.00%, 1/01/23    375  432,184 
Series A-2, 6.00%, 1/01/23    160  184,398 
      2,198,542 
Maine — 1.0%       
City of Portland Maine, RB, General       
(AGM), 5.25%, 1/01/35    1,125  1,184,310 
Michigan — 17.5%       
City of Detroit Michigan, RB:       
Second Lien, Series B (AGM),       
6.25%, 7/01/36    1,800  2,002,122 
Second Lien, Series B (AGM),       
7.00%, 7/01/36    200  234,146 
Second Lien, Series B (NPFGC),       
5.50%, 7/01/29    1,640  1,711,652 
Senior Lien, Series B (AGM), 7.50%,     
7/01/33    1,500  1,827,870 
Senior Lien, Series B (BHAC),       
5.50%, 7/01/35    3,750  3,938,625 
System, Second Lien, Series A       
(BHAC), 5.50%, 7/01/36    2,265  2,374,490 
City of Detroit Michigan, Refunding RB:     
Second Lien, Series E (BHAC),       
5.75%, 7/01/31    2,270  2,455,277 
Senior Lien, Series C-1 (AGM),       
7.00%, 7/01/27    1,650  1,968,202 
Michigan State Building Authority, RB,     
Facilities Program, Series H (AGM),     
5.00%, 10/15/26    375  400,673 
Michigan State Building Authority,       
Refunding RB, Facilities Program,       
Series I (AGC):       
5.25%, 10/15/22    1,350  1,512,824 
5.25%, 10/15/24    615  674,643 
5.25%, 10/15/25    310  337,475 
Royal Oak Hospital Finance Authority     
Michigan, Refunding RB, William       
Beaumont Hospital, 8.25%, 9/01/39  1,265  1,520,606 
      20,958,605 
Minnesota — 2.8%       
City of Minneapolis Minnesota,       
Refunding RB, Fairview Health       
Services, Series B (AGC), 6.50%,       
11/15/38    3,000  3,418,500 
Nevada — 5.0%       
County of Clark Nevada, RB:       
Las Vegas-McCarran International     
Airport, Series A (AGC), 5.25%,       
7/01/39    2,355  2,439,804 
Subordinate Lien, Series A-2       
(NPFGC), 5.00%, 7/01/36    3,500  3,510,220 
      5,950,024 

 

2 BLACKROCK MUNIYIELD INVESTMENT QUALITY FUND

OCTOBER 31, 2010


Schedule of Investments(continued)

BlackRock MuniYield Investment Quality Fund (MFT)
(Percentages shown are based on Net Assets)

    Par   
Municipal Bonds    (000)  Value 
New Jersey — 2.2%       
New Jersey EDA, RB, School Facilities     
Construction, Series Z (AGC), 6.00%,     
12/15/34  $ 1,000  $ 1,145,920 
New Jersey Health Care Facilities       
Financing Authority, RB, Virtua Health     
(AGC), 5.50%, 7/01/38    1,400  1,518,342 
      2,664,262 
New York — 2.8%       
New York City Transitional Finance       
Authority, RB, Fiscal 2009:       
Series S-3, 5.25%, 1/15/39    1,000  1,082,330 
Series S-4 (AGC), 5.50%, 1/15/29  2,000  2,270,980 
      3,353,310 
Ohio — 1.4%       
Ohio Higher Educational Facility       
Commission, Refunding RB, Summa     
Health System, 2010 Project (AGC),     
5.25%, 11/15/40    1,650  1,691,415 
Pennsylvania — 6.8%       
City of Philadelphia Pennsylvania, RB,     
Series C (AGM):       
5.00%, 8/01/35    1,615  1,685,866 
5.00%, 8/01/40    2,880  2,990,189 
Pennsylvania Turnpike Commission, RB,     
Sub-Series B (AGM), 5.25%, 6/01/39  1,455  1,518,903 
Pennsylvania Turnpike Commission,       
Refunding RB, Sub-Series B-1 (AGM),     
5.00%, 12/01/37    1,855  1,933,337 
      8,128,295 
Puerto Rico — 1.4%       
Puerto Rico Sales Tax Financing Corp.,     
RB, First Sub-Series A, 6.38%,       
8/01/39    1,425  1,628,675 
Texas — 21.4%       
City of Austin Texas, Refunding RB,       
Series A (AGM):       
5.00%, 11/15/28    720  779,681 
5.00%, 11/15/29    915  983,790 
City of Dallas Texas, Refunding RB       
(AGC), 5.25%, 8/15/38    850  890,162 
City of Houston Texas, Refunding RB,     
Combined, First Lien, Series A (AGC):     
6.00%, 11/15/35    2,700  3,127,734 
6.00%, 11/15/36    2,055  2,378,930 
5.38%, 11/15/38    1,000  1,097,910 
County of Bexar Texas, RB, Venue       
Project, Motor Vehicle Rental (BHAC):     
5.00%, 8/15/27    1,040  1,119,092 
5.00%, 8/15/28    1,090  1,166,082 
5.00%, 8/15/39    880  917,418 
Frisco ISD Texas, GO, School Building     
(AGC), 5.50%, 8/15/41    1,210  1,332,065 
Harris County Health Facilities       
Development Corp., Refunding RB,     
Memorial Hermann Healthcare       
System, Series B, 7.25%, 12/01/35  500  574,065 
Lower Colorado River Authority,       
Refunding RB, LCRA Transmission       
Services Project (AGC), 5.50%,       
5/15/36    1,155  1,239,546 

 

  Par   
Municipal Bonds  (000)  Value 
Texas (concluded)     
Lubbock Cooper ISD Texas, GO, School     
Building (AGC), 5.75%, 2/15/42  $ 500  $ 543,910 
North Texas Tollway Authority, RB,     
System, First Tier, Series K-1 (AGC),     
5.75%, 1/01/38  1,400  1,549,730 
North Texas Tollway Authority,     
Refunding RB, System, First Tier,     
Series A:     
(AGC), 5.75%, 1/01/40  1,500  1,641,630 
(BHAC), 5.75%, 1/01/48  1,250  1,360,362 
(NPFGC), 5.13%, 1/01/28  3,500  3,680,775 
Tarrant County Cultural Education     
Facilities Finance Corp., Refunding     
RB, Christus Health, Series A (AGC),     
6.50%, 7/01/37  1,100  1,224,311 
    25,607,193 
Utah — 1.4%     
City of Riverton Utah, RB, IHC Health     
Services Inc., 5.00%, 8/15/41  1,670  1,736,132 
Virginia — 1.1%     
Virginia Public School Authority, RB,     
School Financing, 6.50%, 12/01/35  1,100  1,284,261 
Total Municipal Bonds – 129.6%    155,167,026 
Municipal Bonds Transferred to Tender     
Option Bond Trusts (b)     
Alabama — 1.3%     
Mobile Board of Water & Sewer     
Commissioners, RB (NPFGC), 5.00%,     
1/01/31  1,500  1,542,540 
California — 2.2%     
San Diego Community College District     
California, GO, Election of 2002     
(AGM), 5.00%, 5/01/30  2,500  2,644,450 
District of Columbia — 0.7%     
District of Columbia Water & Sewer     
Authority, RB, Series A, 6.00%,     
10/01/35  750  853,810 
Florida — 4.7%     
City of Jacksonville Florida, RB, Better     
Jacksonville (NPFGC), 5.00%,     
10/01/27  1,320  1,356,762 
Hillsborough County Aviation Authority,     
RB, Series A, AMT (AGC), 5.50%,     
10/01/38  2,499  2,577,628 
Lee County Housing Finance Authority,     
RB, Multi-County Program, Series A-2,     
AMT (Ginnie Mae), 6.00%, 9/01/40  810  911,031 
Manatee County Housing Finance     
Authority, RB, Series A, AMT (Ginnie     
Mae), 5.90%, 9/01/40  680  735,573 
    5,580,994 

 

BLACKROCK MUNIYIELD INVESTMENT QUALITY FUND

OCTOBER 31, 2010

3


Schedule of Investments(continued)

BlackRock MuniYield Investment Quality Fund (MFT)
(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender  Par   
Option Bond Trusts (b)  (000)  Value 
Illinois — 2.6%     
Chicago Transit Authority, Refunding RB,     
Federal Transit Administration Section     
5309 (AGM), 5.00%, 6/01/28  $ 2,999  $ 3,147,993 
Kentucky — 0.9%     
Kentucky State Property & Building     
Commission, Refunding RB, Project     
No. 93 (AGC), 5.25%, 2/01/27  1,002  1,110,873 
Nevada — 3.8%     
Clark County Water Reclamation     
District, GO:     
Limited Tax, 6.00%, 7/01/38  2,010  2,270,375 
Series B, 5.50%, 7/01/29  1,994  2,230,319 
    4,500,694 
New Jersey — 1.4%     
New Jersey State Housing & Mortgage     
Finance Agency, RB, S/F Housing,     
Series CC, 5.25%, 10/01/29  1,620  1,711,759 
New York — 5.8%     
New York City Municipal Water Finance     
Authority, RB, Series FF-2, 5.50%,     
6/15/40  1,095  1,235,645 
New York State Dormitory Authority,     
ERB, Series B, 5.25%, 3/15/38  3,250  3,564,762 
New York State Thruway Authority, RB,     
Series G (AGM), 5.00%, 1/01/32  2,000  2,086,080 
    6,886,487 
Texas — 2.4%     
City of San Antonio Texas, Refunding     
RB, Series A, 5.25%, 2/01/31  2,609  2,886,954 
Total Municipal Bonds Transferred to     
Tender Option Bond Trusts – 25.8%    30,866,554 
Total Long-Term Investments     
(Cost – $176,160,046) – 155.4%    186,033,580 
Short-Term Securities  Shares   
FFI Institutional Tax-Exempt Fund,     
0.13% (c)(d)  3,550,614  3,550,614 
Total Short-Term Securities     
(Cost – $3,550,614) – 2.9%    3,550,614 
Total Investments     
(Cost – $179,710,660*) – 158.3%    189,584,194 
Other Assets Less Liabilities – 1.9%    2,260,594 
Liability for Trust Certificates, Including Interest   
Expense and Fees Payable – (13.0)%    (15,581,988) 
Preferred Shares, at Redemption Value – (47.2)%  (56,529,959) 
Net Assets Applicable to Common Shares – 100.0%  $ 119,732,841 

 

* The cost and unrealized appreciation (depreciation) of investments as of

October 31, 2010, as computed for federal income tax purposes, were as

follows:   
Aggregate cost  $ 164,049,509 
Gross unrealized appreciation  $ 10,134,579 
Gross unrealized depreciation  (170,049) 
Net unrealized appreciation  $ 9,964,530 

 

(a) US 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.
(b) Securities represent bonds transferred to a tender option bond trust in
exchange for which the Fund acquired residual interest certificates.
These securities serve as collateral in a financing transaction.
(c) Investments in companies considered to be an affiliate of the Fund
during the period, for purposes of Section 2(a)(3) of the Investment
Company Act of 1940, as amended, were as follows:

      Shares   
  Shares    Held at   
  Held at  Net  October 31,   
Affiliate  July 31, 2010  Activity  2010  Income 
FFI Institutional         
Tax-Exempt         
Fund  8,124,572  (4,573,958)  3,550,614  $ 2,409 

 

(d) Represents the current yield as of report date.

• For Fund compliance purposes, the Fund’s sector classifications refer to
any one or more of the sector sub-classifications used by one or more
widely recognized market indexes or rating group indexes, and/or as
defined by Fund management. This definition may not apply for purposes
of this report, which may combine such sector sub-classifications for
reporting ease.

4 BLACKROCK MUNIYIELD INVESTMENT QUALITY FUND

OCTOBER 31, 2010


Schedule of Investments(concluded)

BlackRock MuniYield Investment Quality Fund (MFT)

•Fair Value Measurements - Various inputs are used in determining the fair
value of investments, which are as follows:

•Level 1 — price quotations in active markets/exchanges for identical
assets and liabilities

•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)

•Level 3 — unobservable inputs based on the best information available
in the circumstances, to the extent observable inputs are not available
(including the Fund's own assumptions used in determining the fair
value of investments)

The inputs or methodologies used for valuing securities are not necessarily
an indication of the risk associated with investing in those securities. For
information about the Fund's policy regarding valuation of investments and
other significant accounting policies, please refer to the Fund’s most recent
financial statements as contained in its annual report.

The following table summarizes the inputs used as of October 31, 2010 in
determining the fair valuation of the Fund's investments:

Valuation Inputs  Level 1  Level 2  Level 3  Total 
Assets:         
Investments in Securities:       
Long-Term         
Investments1  —         $186,033,580  —    $ 186,033,580
Short-Term         
Securities  $ 3,550,614  —    —   3,550,614
Total  $ 3,550,614  $186,033,580  —     $ 189,584,194

 

1 See above Schedule of Investments for values in each state or political
subdivision.

BLACKROCK MUNIYIELD INVESTMENT QUALITY FUND

OCTOBER 31, 2010

5


Item 2 – Controls and Procedures

2(a) – The registrant's principal executive and principal financial officers or persons performing
similar functions have concluded that the registrant's disclosure controls and procedures (as
defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the
31940 Act3)) areeffective as of a date within 90 days of the filing of this report based on the
evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act
and Rule 13a-15(b) under the Securities Exchange Act of 1934, as amended.

2(b) – There were no changes in the registrant's internal control over financial reporting (as defined
in Rule 30a-3(d) under the 1940 Act) that occurred during the registrant's last fiscal quarter
that have materially affected, or are reasonably likely to materially affect, the registrant's
internal control over financial reporting.

Item 3 – Exhibits

Certifications – Attached hereto

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by
the undersigned, thereunto duly authorized.

BlackRock MuniYield Investment Quality Fund

By: /s/ Anne F. Ackerley
Anne F. Ackerley
Chief Executive Officer of
BlackRock MuniYield Investment Quality Fund

Date: December 22, 2010

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, this report has been signed below by the following persons on behalf
of the registrant and in the capacities and on the dates indicated.

By: /s/ Anne F. Ackerley
Anne F. Ackerley
Chief Executive Officer (principal executive officer) of
BlackRock MuniYield Investment Quality Fund

Date: December 22, 2010

By: /s/ Neal J. Andrews
Neal J. Andrews
Chief Financial Officer (principal financial officer) of
BlackRock MuniYield Investment Quality Fund

Date: December 22, 2010