Just as venture capitalists measure a start-up’s financial performance to gauge the success of their investment, venture philanthropists — those who make grants using venture capital strategies — want to measure the impact of their charitable contributions.

Yet figuring out how exactly to measure social impact has long been a challenge for philanthropists.

A new Web-based software program, unveiled Thursday at the Clinton Global Initiative in New York, aims to help foundations and grantmakers solve this problem. It sets benchmarks for measuring social impact, tracks grantees’ performance and compares their performance to other non-profits doing similar work.

Money-market rates may rise in Europe after talks on a U.S. government rescue plan for banks stalled and regulators seized Washington Mutual Inc., deepening concern financial institutions will hoard cash and curb lending.

One-month dollar loans were trading at 4.4 percent, according to Patrick Jacq, a fixed-income strategist in Paris at BNP Paribas SA, France’s biggest bank. The London interbank offered rate for such loans was at 3.71 percent yesterday, the highest since January. Three-month loans were at 4.6 percent, Jacq said, compared with yesterday’s 3.77 percent Libor.