In this file photo, Microsoft Chief Executive Officer Steve Ballmer delivers a preshow keynote address at the 2011 International CES in Las Vegas on Jan.
In this file photo, Microsoft Chief Executive Officer Steve Ballmer delivers a preshow keynote address at the 2011 International CES in Las Vegas on Jan. 5, 2011. (Photo by Gene Blevins/LA Daily News file)

Former Microsoft CEO Steve Ballmer has agreed to buy the Los Angeles Clippers for $2 billion, an amount that would more than triple the top price ever paid for an NBA franchise.

A source close to the negotiations confirmed the agreement, which was signed by Ballmer and Clippers co-owner Shelly Sterling. The Los Angeles Times first reported Ballmer's agreement on Thursday afternoon.

Ballmer is worth an estimated $20 billion, according to Forbes, which ranks him as the world's 35th richest man. Though the deal still requires the approval of the NBA, the league had vetted Ballmer last year during his unsuccessful attempt to buy the Sacramento Kings. The league has not yet indicated how it will respond.

The deal may also need to fend off a fight from controlling owner Donald Sterling, who was banned from the league for life last month after TMZ published audio of his racist comments. Shelly Sterling — who co-owns the team in a family trust — had obtained written consent from him to manage the sale, but Donald has since reversed course and publicly vowed to fight the sale.

However, ESPN reported Thursday night that experts had declared Donald Sterling mentally incapacitated, leaving Shelly Sterling as the sole trustee with the power to sell the team.

Donald Sterling's attorney Maxwell Blecher had indicated a pending legal battle earlier Thursday afternoon.

“He is resisting and will resist any sale of the team forced by the NBA,” Blecher said by e-mail.

Asked if Donald Sterling would be amenable to voluntary sale if the league's June 3 hearing to terminate his ownership is delayed, Blecher said: “If that occurs — which we doubt — we'll see where it leads.”

If a $2 billion sale is finalized, the Clippers would fetch the second-largest price ever in North American pro sports, behind the $2.15 billion the Los Angeles Dodgers sold for in 2012. It would also shatter the record for the sale of an NBA franchise, currently set by the Milwaukee Bucks' $550 million price tag earlier this month.

The staggering number could ripple through professional sports, setting a new baseline for team valuations. Some sports investment bankers said the price likely rose in part to unique factors, such as the compressed bidding time frame and the desire to be the person who helped the league rid itself of Donald Sterling.

Another said that paying more than $1 billion for a major-market franchise is “reasonable,” but compared the Clippers' bidding process to “uncharted waters.” Regardless, the result will make other owners ask higher prices in any future sales.

“It will in the mind of every current NBA owner,” said Robert Caporale, chairman of Game Plan LLC and an adviser on several past NBA franchise purchases. “They will all believe their team is now worth as much money. But that always happens. The market tends to stabilize, but ... it will have an effect not only in the NBA, it could have an effect across all of sports.”

In Ballmer, the Clippers would get an owner with deep pockets and strong ties to the tech world. His bid to buy the Kings with Seattle investor Chris Hansen fell short, but revealed a man who possessed both vision and a willingness to spend.

A league source familiar with those negotiations lauded Ballmer and Hansen for the way they handled Kings employees and the press, and the plan they laid out for the organization.

“Hansen was the spokesperson and Ballmer was the money behind it,” said the source. “They were in concert with everything that happened. They were going to have Phil Jackson as their GM. They were looking for quality at every turn. They had people in mind for every position in the organization the day before they started to bid on the Kings.

“That's how thorough and precise they were. Ballmer was the passion and energy behind it and Chris had more of the even-keeled business approach behind it. Steve was at meetings pumping his fist and pounding tables and was more of the ‘Rah, rah guy' behind the operation. Many said he was the most intense guy they ever dealt with.”

Although Ballmer lives in Seattle, fans in the Northwest shouldn't hold out hope for a franchise. The NBA would be unlikely to approve such a move, and Ballmer has said publicly that he would keep the Clippers where they are.

In fact, it was his insistence on moving the Kings to Seattle that helped sink his bid a year ago. The league source said Ballmer and Hansen misjudged how entrenched the Sacramento fan base was, adding that then-commissioner David Stern was also “hellbent” on keeping the franchise there as part of his legacy.

“If I get interested in the Clippers, it would be for Los Angeles,” Ballmer told The Wall Street Journal two weeks ago. “I don't work anymore, so I have more geographic flexibility than I did a year, year-and-a half ago. Moving them anywhere else would be value destructive.”

Fans and civic leaders are eager for the transition. While Donald Sterling may still fight a sale, Los Angeles City Council President Herb Wesson said Thursday he was surprised at how quickly negotiations to sell the team were progressing.

“This is happening on a faster pace than any of the professionals thought it would go,” Wesson said.

NBA FRANCHISE PURCHASES

The apparent $2 billion winning bid to buy the Clippers would be the most expensive NBA franchise purchase by far:

$550 million: Wesley Edens and Marc Lasry, Milwaukee Bucks, 2014

$450 million: Peter Guber and Joe Lacob, Golden State Warriors, 2010

$350 million: Robert J. Pera, Memphis Grizzlies, 2012

$348 million: Vivek Ranadivé, (65% of the team), Sacramento Kings, 2013

$338 million: Tom Benson, New Orleans Pelicans, 2012

Former Microsoft CEO Steve Ballmer has agreed to buy the Los Angeles Clippers for $2 billion, an amount that would more than triple the top price ever paid for an NBA franchise.

A source close to the negotiations confirmed the agreement, which was signed by Ballmer and Clippers co-owner Shelly Sterling. The Los Angeles Times first reported Ballmer's agreement on Thursday afternoon.

Ballmer is worth an estimated $20 billion, according to Forbes, which ranks him as the world's 35th richest man. Though the deal still requires the approval of the NBA, the league had vetted Ballmer last year during his unsuccessful attempt to buy the Sacramento Kings. The league has not yet indicated how it will respond.

SPORTS FRANCHISE PURCHASES

If the NBA agrees to sell the Clippers to former Microsoft CEO Steve Ballmer for $2 billion, it would be the second-most expensive sports franchise purchase of all time — and in the city of Los Angeles:

Los Angeles Dodgers: $2.15 billion (2012)

Manchester United soccer team: $1.47 billion (2005)

Miami Dolphins NFL team: $1.15 billion (2009)

Chicago Cubs baseball team: $845 million (2009)

Jacksonville Jaguars NFL team: $770 million (2009)