I've yet to come across a grant making organization with too much money and not enough potential grantees.  Rather, the organization's challenge is in figuring out how to maximize the impact of their grantmaking.  Doing this requires a process for both estimating and valuing the impact of each and every grant.  Unfortunately, grants come in every shape, size, and color.  Creating a common lens to facilitate this analysis is no easy task.  But the Bill and Melinda Gates Foundation has summarized some of the best methods of doing just this, in practice by top nonprofits and foundations today. 

For everybody from grantmakers to fundraisers, this white paper is well worth a read.