On Wednesday, Microsoft Corp. co-founder Bill Gates and billionaire investor Warren Buffett released a list of wealthy families and individuals who have joined their six-week old campaign to give at least half their wealth to charity.
Asked about the pledge, Whitman on Tuesday said she and husband Griffith Harsh have made substantial contributions to their own charitable foundation.
Whitman has also donated $91 million this year alone -- to her own gubernatorial campaign.
Whitman was ranked 326th on Forbes' list of 400 richest Americans in 2009. The magazine estimated the Republican candidate's wealth at $1.3 billion in March.