Plans for a new ballpark, record attendance and an increase in sponsorship lifted the Yankees' value 17 percent from the magazine's estimate for last year, said Kurt Badenhausen, an associate editor at Forbes. New York had an operating loss of $25 million last year because the team had a $200 million payroll and paid $105 million in revenue-sharing and luxury taxes.

"Only in baseball could the most valuable team also be the only one to lose money," Badenhausen said.

Baseball's 29 other teams made money, generating profit of almost $500 million, according to Forbes. The sport drew a record 76 million fans last year and signed national television contracts with News Corp.'s Fox and Time Warner Inc.'s Turner Sports worth more than $3 billion.

The average franchise is worth $431 million, produces $170 in revenue and makes $16.5 million, according to Forbes.

The New York Mets are the second-most valuable team at $736 million. The club broke ground on a new stadium and started a sports network that it co-owns with Time Warner and Comcast Corp., leading to a 22 percent increase in value compared with last year.

The Boston Red Sox are third at $724 million, followed by the Los Angeles Dodgers at $632 million and the Chicago Cubs at $592 million.

Marlins Were Least Valuable

The Florida Marlins, baseball's least valuable at $244 million, also posted the largest profit at $43 million. The team cut its payroll to $19 million last year from $75 million as it lobbied the state for a new stadium.

The Marlins are also one of the biggest beneficiaries of the sport's policy for large-market teams such as the Yankees to share money with small-market clubs.

"Their payroll was a fraction of what other low-revenue teams was," Badenhausen said.

The Minnesota Twins posted a 33 percent increase in value, the most in baseball, to $288 million. The Twins reached an agreement with government officials for a new ballpark after years of negotiations.

"When teams secure financing for a new stadium, that is when you get a really big bump in value," Badenhausen said. He said the value increases because it's expected the team will bring in more revenue from sales of suites and premium seating.