Oct. 25, 2010 - Chevron gave $1.25 million late last week to oppose Prop. 25, making them the largest contributor to the campaign with a total of $3.75 million in contributions. The California Chamber of Commerce, the second largest contributor, has given almost $3.1 million, including a $250,000 contribution on Friday. Total contributions to oppose Prop. 25 have reached $15.6 million, while contributions from supporters, primarily unions, are at almost $11.2 million.