Caesars Sportsbook opened with the Astros as -150 favorites over the Braves after Atlanta finished off the Los Angeles Dodgers on Saturday night in the National League Championship Series to earn its spot in the World Series. The price has since ticked down to Houston -145, with the Braves listed at +125.
Game 1 of the World Series is Tuesday night in Houston.
The Astros are in the World Series for the third time in five seasons and have some sportsbooks facing a significant liability. In late June, Houston furniture store owner Jim "Mattress Mack" McIngvale placed $3.35 million in bets on the Astros to win the World Series at around 10-1 odds.
McIngvale regularly uses the betting market to hedge promotions at his store. His largest reported bet on the Astros, $2 million at 10-1 at Caesars Sportsbook, would pay a net $20 million and be one of the largest payouts ever at a U.S. sportsbook.
Atlanta did not look like a World Series contender for much of the season. The Braves' World Series odds drifted to around 40-1 in mid-July after All-Star Ronald Acuna Jr. suffered a season-ending torn ACL.
The Braves didn't climb above .500 until Aug. 6, making them the first team to reach the World Series despite not having a winning record until that late in the season, according to the Elias Sports Bureau.