Actor Brad Pitt's $100,000 donation last week to the campaign opposing a November ballot measure that would ban same-sex marriage in California was the largest thus far by an A-list celebrity.

But it accounts for a small percentage of the roughly $30 million collected by supporters and opponents of Proposition 8, in donations ranging from $20 to seven-figure sums.

As both sides ramp up their campaigns – opponents rolled out their first television ad Monday and supporters plan to do so later this month – they're matching each other dollar-for-dollar with contributions from around the nation.

Supporters of Proposition 8, which would reverse a state Supreme Court ruling that overturned a ban on gay marriage in California, reported raising $14.7 million through last week. Opponents had brought in $13.5 million.

"Our objective is to raise $20 million," said Frank Schubert, the Yes on 8 campaign manager.

Steve Smith, who is managing the No on 8 campaign, said opponents will remain competitive.

"My guess is that by the time this is over, we're going to be within a million bucks of each other," Smith said.

In 2000, when voters approved Proposition 22, which restricted marriage to a man and a woman, opponents were outspent by nearly a 2-1 margin.

This year, many of the same players are involved. The "yes" campaign is getting its biggest donations from Christian and conservative groups, while gay rights groups are leading the "no" side.

Both sides are also making use of the Internet to raise money from small contributors.

Leading the effort to overturn gay marriage is the Connecticut-based Knights of Columbus. The Catholic fraternal organization has contributed $1.25 million, according to campaign finance statements on the secretary of state's Web site.

The National Organization for Marriage, a Mormon group with a branch in California, has contributed about $1 million.

Focus on the Family, the Colorado Springs, Colo., group headed by evangelist James Dobson, donated $650,000. Fieldstead & Co., owned by financier Howard Ahmanson, contributed $600,000, and the Mississippi-based American Family Association pitched in $500,000.

The largest individual contributor is John Templeton Jr. of Bryn Mawr, Pa., a retired pediatric surgeon whose foundation applies scientific methodology to the study of religious issues. He gave $900,000.

Other Yes on 8 donors include Elsa Prince, the matriarch of a prominent Michigan family, who gave $650,000; Robert Hurtt, a former state senator from Orange County, who contributed $250,000; and William Bolthouse, a San Luis Obispo County businessman who made a $100,000 contribution.

Sacramento-area donors include Kevin Moss, a Granite Bay investor who contributed $100,000 and Folsom attorney Andrew Pugno, who donated $35,000.

Leading the opposition is Equality California, a gay rights group, which contributed nearly $4 million and the Human Rights Campaign, a Washington, D.C., gay rights group that gave about $2 million.

The California Teachers Association, California State Council of Service Employees, and Pacific Gas and Electric Co. each contributed $250,000 to the "no" campaign.

Top individual opponents include Utah businessman Bruce Bastian, co-founder of the WordPerfect software company, $1 million; David Maltz, a Cleveland businessman, $750,000; and Beverly Hills lawyer David Bohnett, $500,000.

Other opponents include former congressman Michael Huffington, $100,000, and Hollywood producer David Geffen, $50,000.

Pitt, who has increasingly devoted himself to humanitarian causes since he began his relationship with actress Angelina Jolie, publicly announced his contribution.

In a statement, Pitt said he opposes Proposition 8 because "discrimination has no place in America."

"Everyone has the right to live the life they so desire if it doesn't harm another," he said.

Pitt's political adviser, Trevor Neilson, told the Associated Press the actor was surprised that his colleagues in the entertainment industry had not donated more money.

But Smith, the No on 8 campaign manager, said, "Hollywood plays much more heavily in candidate campaigns than (it) does in issues campaigns."

Schubert, the Yes on 8 campaign manager, said the campaign picked up support after the state Supreme Court overturned Proposition 22 in May.

"This is an issue that involves one of the fundamental understandings in civilization – that marriage has always been between a man and a woman," Schubert said.

Call Aurelio Rojas, Bee Capitol Bureau, (916) 326-5545.