Minutes after the Cincinnati Bengals beat the Buffalo Bills to set up an AFC Championship rematch with the Kansas City Chiefs, the Chiefs opened as a 1.5-point favorite in BetMGM's NFL odds.
By Monday, the Chiefs were an underdog, floating between +2.5 and +1.5. If they're still an underdog by kickoff on Sunday evening, it'd be the first the Chiefs are a postseason dog since a divisional round loss to the New England Patriots in January 2016. And it'd be the first time they're a home postseason dog since a Wild Card loss to the Baltimore Ravens in January 2011.
Here's a look at NFL betting in conference championships over the last two decades:
If the line holds, the Chiefs would be just the seventh home underdog in a conference championship since the 2003-04 NFL season.
The six home dogs before them are 3-3 against the spread. Most recently, the Philadelphia Eagles narrowly covered +3 in a 38-7 win over the Minnesota Vikings seven years ago.
In each game, the underdog also won outright, i.e., home dogs are 3-3 against the moneyline.
The Over Is Dominating...
The under hit in both the AFC Championship and NFC Championship last year, as it did in both conference championships in January 2004.
In the 18 years between those two seasons, the under went 9-22-3.
Even with an 0-2 mark last year, the over has hit in nine of the last 13 conference championships, including in all three of the Chiefs' appearances from January 2019 through January 2021.
And when the over hits, it comfortably hits; in those nine over games since January 2016, the over has hit by an average of seven points.
...But Not in Windy Games
As of Wednesday, forecasted winds for GEHA Field at Arrowhead Stadium are between 11-13 mph.
Since January 2004, nine outdoor conference championships have been played with an average wind speed of at least 10 mph. The over is 2-5-2 (.286) in those games.
How does that compare to all postseason and regular-season NFL games with winds of at least 10 mph?
In 48 postseason instances over the last 20 years, the over is 17-29-1 (.370).
In more than 1,000 regular-season instances, the over is 460-574-8 (.445).
Deebo Samuel's 44-yard touchdown and Robbie Gould's 38-yard field goal in the final seven minutes of the first half of last year's NFC Championship gave the San Francisco 49ers a three-point halftime lead, 10-7, that covered the first-half spread (+2.5).
That's one of only four first-half covers by road teams in the last 15 conference championships.
Home teams are 10-4-1 against the first-half spread since the New England Patriots covered against the Indianapolis Colts in January 2015. The Chiefs account for two covers, one loss, and one push over that time, most recently covering -2.5 against the Bengals last year.
You can view updated conference championship odds and more NFL betting opportunities at the BetMGM online sportsbook.