AMENDMENT NO. 2 TO CAPITAL SUPPORT AGREEMENT

Exhibit 10.2

AMENDMENT NO. 2 TO

CAPITAL SUPPORT AGREEMENT

This Amendment No. 2 (the “Amendment”) to the Capital Support Agreement, is made as of the 29th day of September 2008, by and between NORTHERN TRUST CORPORATION (the “Support Provider”) and NORTHERN INSTITUTIONAL FUNDS (the “Trust”), on behalf of its series the Prime Obligations Portfolio (the “Fund”).

WHEREAS, the parties have entered into a Capital Support Agreement (the “Agreement”), dated as of February 21, 2008 and amended the Agreement on July 15, 2008; and

WHEREAS, the Support Provider wishes to increase the level of capital support provided to the Fund; and

WHEREAS, the parties desire to further amend the Agreement on the terms and subject to the conditions provided herein;

NOW THEREFORE, the parties, intending to be legally bound, hereby agree as follows:

1. Unless otherwise expressly provided herein, capitalized terms shall have