Articles Supplementary

BLACKROCK INDEX FUNDS, INC.

/s/ Janey Ahn

/s/ John M. Perlowski

John M. Perlowski

President and Chief Executive Officer

Exhibit 1(o)

BLACKROCK INDEX FUNDS, INC.

ARTICLES SUPPLEMENTARY

BLACKROCK INDEX FUNDS, INC., a Maryland corporation (the “Corporation”), hereby certifies to the State Department of Assessments and Taxation of the State of Maryland that:

FIRST: The Corporation is registered as an open-end company under the Investment Company Act of 1940, as amended, with the authority to issue 8,248,000,000 shares of capital stock as follows:


Series and Classes	Number of Authorized Shares
iShares Russell 2000 Small-Cap Index Fund
Investor A Common Stock		208,000,000
Institutional Common Stock		208,000,000
Class K Common Stock		1,208,000,000
Investor P Common Stock		2,000,000,000
iShares MSCI EAFE International Index Fund
Investor A Common Stock		208,000,000
Institutional Common Stock		1,208,000,000
Class K Common Stock		1,208,000,000
Investor P Common Stock		2,000,000,000
Total:		8,248,000,000

All shares of all classes of the capital stock of the Corporation have a par value of $0.0001 per share and an aggregate par value of $824,800.

SECOND: Pursuant to authority expressly vested in the Board of Directors of the Corporation by Sections 2-105(c), 2-208, and 2-208.1 of the Maryland General Corporation Law and the Corporation’s charter, the Board of Directors hereby increases the total number of authorized shares of capital stock of the Corporation by 800,000,000 and designates such newly authorized shares as Class G Common Stock (the “Class G Common Stock”) of iShares MSCI EAFE International Index Fund Series.

THIRD: After the increase in the number of authorized shares and the designation and classification of capital stock of the Corporation set forth herein, the Corporation will have the authority to issue 9,048,000,000 shares of capital stock as follows:


Series and Classes	Number of Authorized Shares
iShares Russell 2000 Small-Cap Index Fund
Investor A Common Stock		208,000,000
Institutional Common Stock		208,000,000
Class K Common Stock		1,208,000,000
Investor P Common Stock		2,000,000,000
iShares MSCI EAFE International Index Fund
Investor A Common Stock		208,000,000
Institutional Common Stock		1,208,000,000
Class K Common Stock		1,208,000,000
Investor P Common Stock		2,000,000,000
Class G Common Stock		800,000,000
Total:		9,048,000,000

All shares of capital stock of the Corporation will have a par value of $0.0001 per share and an aggregate par value of $904,800.

FOURTH: The preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends, qualifications, and terms and conditions of redemption of the Class G Stock are identical to the preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends, qualifications, and terms and conditions of redemption of the other classes of stock of iShares MSCI EAFE International Index Fund Series.

FIFTH: These Articles Supplementary shall be effective as of the 28th day of July, 2023.

[signatures on next page]

IN WITNESS WHEREOF, BLACKROCK INDEX FUNDS, INC. has caused these Articles Supplementary to be signed in its name and on its behalf by the person named below who acknowledges that these Articles Supplementary are the act of the Corporation and that, as to all matters and facts required to be verified under oath and to the best of his knowledge, information, and belief under the penalties of perjury, the matters and facts set forth herein are true in all material respects, as of this 27^th day of July 2023.