Journalist, Mike Royko, once observed that “hating the New York Yankees is as American as pizza pie, unwed mothers, and cheating on your income tax.” At the time he was complaining about the 22 World Series championships they had won. (They’ve since won 5 more).

So it’s hard to argue with Yankee fans because they feel the team is so valuable to them. But now, according to Forbes, the New York Yankees is the most valuable brand in sports, adjudged to be worth $1.6 billion, with a brand name value of $328 million.

While that valuation may have agitated baseball fans of other teams and surprised some marketers, it merely confirms the findings of this year’s Brand Keys Sports Loyalty Engagement Index where, once again for the 18th year in row, the New York Yankees show up in the top-5 for the most-loyal fans in baseball. This year, this is how the teams ranked:

1. Boston Red Sox
2. New York Yankees
3. Philadelphia Phillies
4. Anaheim Angels/Los Angeles Dodgers
5. Minnesota Twins/Milwaukee Brewers/Houston Astros

The Sports Loyalty Engagement Index gives an apples-to-apples comparison of the intensity with which fans support their home teams, with insights that ID areas that need strategic reinforcement. Managed correctly by a team, increased loyalty is always accompanied with increased broadcast viewership, merchandise purchases, sponsorships, and ticket revenues. Oh, and yes, happier fans. Everybody loves a winner, but win/loss ratios alone do not entirely govern fan loyalty, even if you’ve got 27 World Series Championships.

Yes, everyone claims that their home team has the most-loyal fans, but ultimately it’s the bottom line that proves why loyalty is a leading-indicator of positive consumer behavior and profitability. Gross sales of Yankees championship-emblazoned products came to $450 million last year. The new ballpark spurred a 40% growth in sponsorship revenue, and local TV ratings on the YES Network were up 11%, as most baseball teams saw their ratings decline.

Yankee detractors (often Boston Red Sox fans evoking “The Curse”) think that the Yankees have just been lucky. And while that may be part of it, one sure thing is that luck always changes. But when it comes to loyalty, it’s always a sure thing that a brand with loyal fans will win – no matter what field you’re playing on.