Proposition 39, which could raise $1 billion by closing an out-of-state tax loophole, won easily Tuesday.

The measure maintained a strong lead throughout the night.

Tom Steyer was the about the only deep-pocketed individual who avoided attacks for pouring tens of millions of dollars into a ballot measure this year.

Steyer, the wealthy Bay Area hedge fund manager and environmentalist, authored Proposition 39 in an effort to bring $1 billion a year to the state by closing a loophole that allows out-of-state corporations to choose how they're taxed.

"This is the beginning of a new comeback for California," Steyer told a crowd of labor volunteers at a victory party for his measure, as well as Propositions 30 and 32. "This is a loophole that should have been closed. This win means sometimes people have to stand up for themselves."

Under the measure, out-of-state businesses will have to calculate their tax liability based on the percentage of their sales in California.

Of the $1 billion raised per year under Proposition 39, half will fund energy-efficiency and clean-energy projects at public buildings and schools for the first five years, creating 40,000 new jobs, according to the state Legislative Analyst's Office. The other half will go to the general fund. Thereafter, the full $1 billion annually will go to the general fund -- $91.3 billion this fiscal year.

Steyer, who bankrolled Proposition 39 with $30 million, was able to sidestep an opposition campaign that had been promised by the likes of tobacco giant Philip Morris, personal product company Kimberly-Clark, General Motors, Chrysler, International Paper and Procter & Gamble.

The reason the measure was even on the ballot was that the Legislature approved the giveaway in 2009 to out-of-state corporations in an end-of-session deal lawmakers made to win passage of a temporary increase in income and sales taxes.

Big business used its muscle on several occasions to rebuff efforts to roll back the tax break. On the final day of the legislative session, Philip Morris and Kimberly-Clark, with Republican support, killed legislation that would have closed the same tax break and put the savings into college tuition breaks.

But the giant multinational corporations were intimidated by Steyer's money and his willingness to take direct shots at each of the companies in what would have been huge public-relations hits for them.

Steyer, who recently resigned as chairman of his $20 billion financial firm, San Francisco-based Farallon Capital Management, to devote himself more fully to politics. He's rumored to be interested in the governorship, and he made a first step toward that by joining forces with labor groups to campaign for Proposition 30, Gov. Jerry Brown's tax-hike initiative, and against Proposition 32, aimed at curbing labor's ability to raise political cash.

Contact Steven Harmon at 916-441-2101. Follow him at Twitter.com/ssharmon. Read the Political Blotter at IBAbuzz.com/politics.