American Pharoah's Triple Crown triumph was great news for those who placed big bets on the winning horse Saturday in the Belmont Stakes, but is it a bad omen for investors?

If you believe certain historical stock market statistics, the answer could be yes -- although some experts are quick to say such statistics are a bad bet for investors to follow.

With one exception, the U.S. stock market has stumbled for the rest of the year after a Triple Crown win, according to an analysis of a key stock index, the Standard & Poor's 500, by Harrison-based Bespoke Investment Group.

Before American Pharoah, 11 thoroughbreds have claimed the Triple Crown. Ten of those wins have taken place since 1928, when S&P 500 record-keeping began.

On average, after those 10 victories, the S&P 500 has fallen by slightly more than 9 percent for the rest of year, Bespoke reported.

By contrast, the index has gained 5 percent on average in the years when no horse won first place in all three Triple Crown races -- the Kentucky Derby, the Preakness and the Belmont Stakes -- the firm reported.

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Is there anything to this? One economist's answer is a firm nay.

"It doesn't mean a thing," said Michael Zweig, an economist and director of the Center for Study of Working Class Life at Stony Brook University.

But couldn't a herd mentality kick in, with investors bolting from stocks out of fear that others will do the same?

The impact of a few skittish investors selling for such a silly reason would be far outweighed by the effects of interest rates, employment and other global trends, Zweig said.

"The Triple Crown winner is irrelevant to any of that," he said. "It's random, it's chance."

Even the company that reported on the link was quick to caution investors against acting on it.

"It's not like there's anything fundamentally tying the S&P 500 to a horse race, or a trio of races," George Pearkes, an analyst at Bespoke, said with a laugh. "It's just one of those things where two series of numbers just coincidentally go in the same direction."

Bespoke's report was made with "a wink and a smile," said Barry Ritholtz, a Manhattan-based money manager and columnist who lives in Locust Valley.

"The advice to investors is really simple: Have a long-term plan," he said. "The day-to-day stuff is just noise, it's just a huge distraction."