Stock market investors hoping to extend the nearly nine-year bull market should cheer for the Philadelphia Eagles in Super Bowl LII on Sunday.
That's the message from believers in the Super Bowl Predictor, a whimsical but remarkably accurate prognosticator of the market's behavior for the last 50 years long touted by Sarasota market analyst Robert Stovall.
But hold on, fans of the New England Patriots. New research shows that when a former Super Bowl champ wins again — the Pats are five-time victors — the average market return that year hits double digits.
The Predictor holds that the stock market will rise in a year when an original member of the National Football League or of the current National Football Conference wins the Super Bowl. The Eagles are this year's NFC champs.
But when a team from the old American Football League or the current American Football Conference, such as the Patriots, is victorious, stocks will retreat.
The Predictor, while completely unscientific, has been on the money 40 out of 51 times, for an 80 percent accuracy rate.
But it fumbled in 2016 and 2017 after a seven-year winning streak. The Patriots won Super Bowl LI last year, but all the major market indexes soared to new highs. The Dow closed 2017 up 25 percent, the S&P gained 19 percent and the Nasdaq jumped 28 percent.
Stovall has acknowledged the Predictor is not infallible, but has noted that "It still outperforms most gaggle of gurus or economic models that I'm aware of."
Meanwhile, S&P Global Market Intelligence has come up with some light-hearted pre-game research that could sway investors into cheering for either team.
In addition to market returns averaging 13.2 percent on the S&P 500 after a repeat champ wins, when the home team wins the average return is 16.3 percent versus 8.6 percent for a road team win. The Patriots are the designated home team in Minneapolis.
But with a first-time victory from an NFC team — the Eagles have lost their only two Super Bowl appearances — the market gains an average 15.9 percent.
The betting line also can matter. The Pats were 4 1/2-point favorites on Thursday, with the line for total points scored at 48.
"When the favored team wins, the market responds with an average return of 13.1 percent versus 9.6 percent when the underdog pulls off the upset," S&P Global said. "No matter who wins, the market likes it when the game goes 'over' as the market responds with an average return of 16.7 percent."
Super Bowl LII will be played indoors at U.S. Bank Stadium. During the 17 games held under a dome or closed retractable roof, the average market return was 6.6 percent. In the 34 games played in open-air or open-roof stadiums, the S&P returned an average 14.3 percent.
"This will be the fifth time that the Super Bowl is played in a cold-weather city, but the market seems warm to the idea as the average return in the year following each cold-weather city appearance is 14.9 percent," S&P Global said. "The market had a return of 7.6 percent when Super Bowl XXVI was played in the state of Minnesota."
Of course, neither the Predictor nor the S&P Global findings should be the basis for any investment decisions. Stovall has noted the Predictor's success is tilted by the fact that more teams are linked to the NFL than the AFL, including several current AFC teams, and the stock market historically goes up more years than it goes down.