SAN FRANCISCO  (AP) — Warren Buffett has already helped raise nearly $15 million over the years for a San Francisco homeless charity, and the group hopes someone will again be willing to pay more than $2 million for a private lunch with the Omaha, Neb., investor.

There are no guarantees someone will pay that much for a private audience with the billionaire chairman and chief executive of Berkshire Hathaway.

But the auction has become a significant part of the Glide Foundation’s annual $17 million budget for helping the poor and homeless in San Francisco. Last year’s winner paid $3,456,789, and the winning bids have topped $2 million for the past five years.

Glide founder Rev. Cecil Williams said it would be incredible if the auction attracted another multimillion-dollar bid.

“What a life we would live, if the bids keep increasing,” Williams said.

Bidding for the lunch on eBay will begin at $25,000 on the evening of June 2 and continue through June 7. But the bids don’t typically reach astronomical levels until close to the end of the auction.

Buffett has said the bidding on the lunch auction, which is the only one he does all year, has surpassed anything he expected.

Buffett has supported Glide since his late first wife, Susan, introduced him to Williams because he’s been impressed with the way they go about helping people.

“There’s all kinds of people that need that kind of help, and I don’t think anybody is better at providing it than Glide,” Buffett said.

Williams said he is grateful for everything Buffett has done to help the charity he started 50 years ago, adding that his staff will continue to find ways to help the poor regardless of how much money the auction raises.

“We will continue the race, and we will continue the work,” Williams said.

Traditionally the winners of the auction spend several hours with Buffett at New York’s Smith and Wollensky steak house, but in some years the winner wants to remain anonymous so the lunch happens elsewhere. The steak house donates at least $10,000 to Glide each year to host the auction lunch.

Buffett said he gets a variety of questions at the lunches, and not just about business and investing. The only topic that’s off limits is what he is planning to invest in next.

Many of the questions deal with subjects such as philanthropy because Buffett has been gradually giving his fortune away since 2006. He plans to divide most of his Berkshire stock between five charitable foundations, with the largest chunk going to the Bill and Melinda Gates Foundation.

Buffett has said that it’s unlikely he will hire another one of the auction winners as he did after Ted Weschler paid a total of nearly $5.3 million to win the 2010 and 2011 auctions.

Weschler is one of two investment managers Buffett hired to help manage Berkshire’s portfolio and eventually oversee the company’s investments after the 82-year-old Buffett dies. Buffett has said Berkshire doesn’t need any additional money managers.

Buffett’s company owns roughly 80 subsidiaries including insurance, furniture, clothing, jewelry and candy companies, restaurants and natural gas and corporate jet firms, and has major investments in such companies as Coca-Cola Co. and Wells Fargo & Co.