To amend the Internal Revenue Code of 1986 to modify the rate of the excise tax on investment income of private foundations, and for other purposes.

Amends the Internal Revenue Code to: (1) reduce between 2010 and 2015 the excise tax rate on the net investment income of tax-exempt private foundations from 2 to 1.32%; and (2) suspend between 2010 and 2015 the 1% reduction in such tax rate for private foundations that meet certain distribution requirements.

Directs the Secretary of the Treasury to conduct and submit to Congress by December 31, 2013, a study which examines the effect of the tax rate changes of this Act on the level of grantmaking by private foundations.