The Cubs are listed as small favorites, around -115, at most sportsbooks, with the underdog Cleveland Indians sitting at +105.
Late Wednesday morning at sportsbook operator CG Technology, more than three times as much money had been bet on the Cubs as had been bet on the Indians.
The money was 2-1 in favor of Chicago at MGM's sportsbooks, despite a $40,000 bet on the Indians placed Wednesday morning. The MGM, which fares much better overall with an Indians Game 7 win than with a Cubs victory, bumped up Cleveland's odds to attract the bet, assistant manager Jeff Stoneback said.
"We still need the Indians," Stoneback added.
The sentiment was echoed across Las Vegas.
"We took quite a bit of money on the Cubs, but I wouldn't say it was 'professional' money," Bob Scucci, director of race and sports for Boyd Gaming in Las Vegas, said in an email. "At Cubs -120, we are seeing the well-respected action on Cleveland."
The sportsbooks at the Westgate and the Wynn also took early action on the Cubs, but the larger bets were expected to show up closer to the first pitch.
"We've been taking huge five-figure bets on both sides the last couple of games," Wynn executive director Johnny Avello said. "So where we are right now doesn't mean much."
Trailing the Indians three games to one before the series shifted back to Cleveland on Tuesday, the Cubs were +320 underdogs to win the World Series. William Hill's Nevada sportsbook took 97 bets on Chicago at that point, the largest a $2,200 wager that would net $7,040.
Two large World Series futures bets on Cleveland are also on the line at William Hill.
On Feb. 24, someone placed a $5,000 bet on Cleveland to win the World Series at 30-1 odds. The bettor would net $150,000 with an Indians victory Wednesday night. On June 18, someone bet $10,000 on the Indians at 14-1 odds. That bettor would net $140,000 if Cleveland wins.
The over/under on Game 7 has attracted lopsided action.
The total opened at 7 (-120 under) Tuesday night, but was quickly bet down to 6.5, where it sat Wednesday afternoon.
"We have taken $310 on the over," CG Technology vice president of race and sports Jason Simbal said. "And we have taken just over five figures on the under."
Wednesday night's game matches Indians ace Corey Kluber against Cubs right-hander Kyle Hendricks. If the line holds with the Cubs favored, this will be only the fourth game this season that Kluber has been an underdog.