The New York Knicks are the most valuable professional basketball team in the National Basketball Association for the fourth consecutive year, Forbes magazine reported on Wednesday.

The Knicks' estimated value is US $613 million, up $5 million from last year's list, according to the magazine.

The team, owned by Cablevision Systems Corp, had estimated operating income of $29.6 million for the 2007-2008 season, a large improvement from a loss of $42.2 million the previous year, Forbes said.

The team posted the most revenues in the NBA at $208 million, up from $196 million the year before.

The NBA, like most US sports leagues, has been hit by the economic slump. At the start of the current season, league executives acknowledged weakness in season-ticket sales, and Commissioner David Stern said in October the NBA would lay off 80 people, or 9 percent of its work force.

For the fourth straight year, the Los Angeles Lakers ranked second with an estimated value of $584 million, up from $560 million last year, Forbes said.

In the NBA finals last season, the Lakers lost to the Boston Celtics, which broke into the top 10 at No. 9, with a value of $447 million -- the largest increase in the top 10 from last year at 14 percent. Every team in the top 10 showed an increase in estimated value.

Ranking from three to eight were the Chicago Bulls (with an estimated value of $504 million), the Detroit Pistons ($480 million), the Cleveland Cavaliers ($477 million), the Houston Rockets ($469 million), the Dallas Mavericks ($466 million) and the Phoenix Suns ($452 million), according to Forbes.

The San Antonio Spurs ranked No. 10 with a value of $415 million.

The Miami [Images] Heat, meanwhile, dropped out of the top 10 to No. 12, with a value of $393 million, down from $418 million last year, the magazine said.

The Bulls had the highest estimated operating income at $55.5 million, while the Denver Nuggets suffered the largest estimated loss at $26.3 million, Forbes said.

Among the 10 most valuable teams, the Mavericks, owned by wealthy investor Mark Cuban, had an estimated operating loss of $13.6 million, according to Forbes. In May, Cuban, who was recently charged by federal regulators with insider trading, said his team had lost money in six of the last eight years.

Revenue and operating income for the teams is estimated for the 2007-2008 season, Forbes said. Values are estimated based on teams' arena deals without deducting debt, other than arena debt.