Michael Ozanian, Forbes' executive editor, said the Cowboys' value, which the magazine tabs at $2.1 billion, is "a conservative estimate."
Ozanian said the magazine took into account the Cowboys' $80 million in sponsorship income, their state-of-the art stadium and the fact that they are the only team in the NFL that distributes its own merchandise to retailers.
Jerry Jones bought the Cowboys in 1989 for $140 million. That's roughly a 715 percent increase to today's value, factoring in inflation.
Despite playing in the same stadium, the magazine estimated the net worth of the New York Jets at about $200 million less than the Giants.
"We have the Giants bringing in $27 million more in revenue, plus they're getting the Super Bowl bump on ticket prices," Ozanian said.
Despite the threat of concussion litigation that could eventually cost the NFL billions of dollars, the magazine reports only one franchise -- the Cincinnati Bengals -- lost value from last season.
"There wasn't any loss of value reflected in the recent Cleveland Browns sale," Ozanian said. "The investment bankers we spoke to told us that prices haven't dropped in terms of what people are offering for small or large shares of teams."
Forbes stated that 20 NFL teams are worth more than $1 billion, the most of any league. That number is up from 15 teams last year.
The Bengals are worth $871 million compared to $875 million last season, a drop of less than 1 percent.
Forbes projects only two teams had operating losses last year -- the Pittsburgh Steelers ($1.1 billion), due to a higher payroll, and the Oakland Raiders ($785 million), thanks to having the lowest revenues in the league.
The magazine concluded that the two teams that had the biggest jump in value were the Minnesota Vikings ($975 million) and the San Francisco 49ers ($1.17 billion), whose values jumped 22 and 19 percent, respectively, as a result of stadiums being built.
As has been the case in previous years, the NFL and its clubs did not open all its financials to Forbes.
"I can look at any particular year and have issues with how teams are valued," NFL executive vice president Eric Grubman told ESPN.com. "But over time, Forbes has proven that they are in the right zip code and they also are accurate as to what teams are higher and lower than others based on what happens with subsequent team sales."
The Cowboys' $2.1 billion value matches that of the Los Angeles Dodgers purchase by Guggenheim Partners. Forbes says only Manchester United is worth more. The magazine said the soccer team was worth $2.23 billion, but the team's recent offering on the New York Stock Exchanged valued it at $2.9 billion.