Depending on one's penchant for niche market theories, a Super Bowl win by the Eagles could be just the tonic reeling U.S. equities need.

That's the signal the so-called Super Bowl Indicator is sending. It goes like this: a victory in Sunday's football title game by the National Football Conference representative, in this case the Eagles, will boost stocks in the following week. The market outcome isn't nearly as positive if an American Football Conference team, or the New England Patriots, prevails.

There's no data-backed rationale for the theory to work, but work it does. In 1990, an article published in the Journal of Finance examining the phenomenon decided that "few prediction schemes have been more accurate, and at the same time more perplexing."

CXO Advisory Group LLC looked at the data through last year's game and found that the outcome is good for stocks no matter who wins — but that an NFC victory delivers a gain almost twice as big as an AFC win does. Their analysis suggests investors are distracted in the run-up to the game and return more focused in the week following.

If quant traders at Wells Fargo Asset Management's Analytic Investors LLC are right, Eagles fans and investors alike may be in for a rough week. Their model, which beat the point spread in 10 of the last 14 games, sees a Patriots win by at least five points.