Oct. 22, 2010 - The main backers of Prop. 23 each made large contributions on Friday - Valero Services Inc. gave $1,000,000 and Tesoro Companies gave $500,000. Valero has now contributed more than $5 million and Tesoro has given just over $2 million. Opponents of Prop. 23 have still raised almost three times as much with $30.1 million compared to $10.7 million in total raised by supporters. Large contributors favoring the ballot measure designed to stall California's climate change legislation AB 32 had been silent for most of the week.