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: John M. Perlowski, Chief Executive Officer, BlackRock
MuniYield Investment Quality Fund, 55 East 52^nd 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: 04/30/2011

Item 1 – Schedule of Investments

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BlackRock MuniYield Investment Quality Fund (MFT)
Schedule of Investments April 30, 2011 (Unaudited)
(Percentages shown are based on Net Assets)

 

 

 

 

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BlackRock MuniYield Investment Quality Fund (MFT)
Schedule of Investments (continued)
(Percentages shown are based on Net Assets)

 

 

 

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BlackRock MuniYield Investment Quality Fund (MFT)
Schedule of Investments (continued)
(Percentages shown are based on Net Assets)

 

 

 

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BlackRock MuniYield Investment Quality Fund (MFT)
Schedule of Investments (continued)
(Percentages shown are based on Net Assets)

 

* The cost and unrealized appreciation (depreciation) of investments as of
April 30, 2011, as computed for federal income tax purposes, were as
follows:

(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) When-issued security. Unsettled when-issued transactions were as
follows:

(c) 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.
(d) 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:

(e) 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.

 

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BlackRock MuniYield Investment Quality Fund (MFT)
Schedule of Investments (concluded)

•Fair Value Measurements — Various inputs are used in determining the fair
value of investments and derivative financial instruments. These inputs
are summarized in three broad levels for financial reporting purposes 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 and derivative financial instruments)

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
derivative financial instruments and other significant accounting policies,
please refer to the Fund’s most recent financial statements as contained in
its semi-annual report.

The following tables summarize the inputs used as of April 30, 2011 in
determining the fair valuation of the Fund's investments and derivative
financial instruments:

 

 

 

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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/ John M. Perlowski
John M. Perlowski
Chief Executive Officer of
BlackRock MuniYield Investment Quality Fund

Date: June 24, 2011

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/ John M. Perlowski
John M. Perlowski
Chief Executive Officer (principal executive officer) of
BlackRock MuniYield Investment Quality Fund

Date: June 24, 2011

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

Date: June 24, 2011

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