A season of betting upsets: How bettors lost big on the 2025 NFL underdogs

The 2025 NFL season has been defined by the underdog, with favorites consistently falling in stunning upsets and costing bettors untold millions. While exact betting totals are closely guarded by sportsbooks, industry reports and public data offer a glimpse into the financial devastation caused by some of the year’s most shocking results.

Bills’ Thursday night flop

Last night’s upset of the Buffalo Bills by the Houston Texans was just the latest high-profile example.

• The Bills were strong moneyline favorites, ranging as high as -285 in some markets.
  
  
• A significant amount of the total handle was on Buffalo. For instance, at one major sportsbook, 84% of the money was on the Bills’ moneyline, a massive win for the house.
  
  
• Estimated bettor losses: Although the specific amount isn’t known, sportsbooks confirmed it was a significant day for their bottom line and a “bad day to be the betting public.”
  

Other significant betting upsets of the 2025 season

Here’s a look at some of the other surprising results that have cost bettors dearly this season:

Broncos over Chiefs (Week 11): Kansas City was a 6-point favorite over the Broncos, and yet Denver pulled off the 22–19 upset. Had the heavily bet Chiefs won, it would have been a significant payout for sportsbooks.

Panthers over Falcons (Week 11): Atlanta was a 3.5-point favorite in this divisional matchup, but fell 30–27 to the lowly Panthers.

Bears over Vikings (Week 11): Bettors likely lost big on the Vikings, who were favored over the Bears in their 19-17 loss.

Browns over Packers (Week 3): The Packers were 7.5-point favorites over the Browns, but Cleveland pulled off the shocking 13–10 upset.

Chargers over Chiefs (Week 1): The Chiefs were heavily favored to win their season opener against the Chargers, and their 27–21 loss immediately put bettors in the red.

What does this mean for sports betting?

The frequency of these upsets and the subsequent financial losses for bettors underscore a broader trend:

Increased risks: The increased popularity of parlays, which magnify payouts and losses, means more casual bettors are taking on greater risks.

The house always wins: While individual bettors can have lucky days, sportsbooks thrive on the high volume of bets, particularly on favorites, which they hope will lose.

Vulnerable bettors: Research shows that a high percentage of sports bettors consistently lose money, and events like these only compound those losses.