The Boston Red Sox made the 2026 MLB playoffs, clinching the second American League wild card on September 20 despite a 5-1 loss at Tampa Bay, when Atlanta beat Houston. Boston was 29-43 on June 18, went 58-32 the rest of the way with a 15-game July winning streak, and finished 87-75. Kalshi settled the contract Yes that afternoon and Polymarket resolved it Yes that night.
Resolved September 20, 2026.
The Boston Red Sox made the 2026 MLB playoffs on Sunday, September 20, and they did it on a day they lost. Boston fell 5-1 at Tampa Bay that afternoon, then clinched when Atlanta beat Houston 4-2 a short time later. The Red Sox finished 87-75 as the second American League wild card. In mid-June the club was 29-43 and Kalshi priced its playoff chances at 11%.
| Team | W-L | Wild-card position |
| New York Yankees | 93-68 | 1st wild card |
| Boston Red Sox | 87-75 | 2nd wild card (No. 5 seed) |
| Chicago White Sox | 84-78 | 3rd wild card |
| Texas Rangers | 80-82 | Out |
Records are from the MLB Stats API's final standings. Boston finished third in the AL East, 11 games behind the 98-64 Rays, with a +78 run differential (689 scored, 611 allowed). The Red Sox also won all six games against the White Sox, the team directly behind them in the wild-card table.
Houston's loss capped the Astros at 83 wins, below the 84 wins Boston was already certain to reach. Texas could still reach 84, but only by winning out, which would have made the Rangers AL West champions rather than a wild-card rival. Kalshi settled the Boston contract Yes at 5:49 p.m. ET on September 20. Polymarket closed its contract at 9:25 p.m. ET the same night and resolved it Yes. The Kalshi contract traded about 247K contracts and the Polymarket contract about $5.9K.
Boston's season splits cleanly in two. Through June 18 the Red Sox were 29-43, 15.5 games out of first in the AL East and 6.5 games out of the last wild-card spot. From June 19 through the end of the season they went 58-32.
July was the month that decided it. Boston went 21-4, and its wild-card standing went from 6.5 games out on July 2 to a playoff spot by July 19.
Kalshi end-of-day prices for the Boston contract:
| Date (ET close) | Red Sox | Record |
| Mar 25 (Opening Day) | 60% | 0-0 |
| Jun 18 (low point in the standings) | 11% | 29-43 |
| Jul 2 (eve of the streak) | 14% | 37-48 |
| Jul 21 (day 14 of the streak) | 61% | 51-48 |
| Aug 7 (end of nine-game streak) | 96% | 64-51 |
| Aug 20 (30 days out) | 91% | 68-59 |
| Sep 19 (day before clinch) | 99% | 84-71 |
The preseason market liked Boston at 60%, then spent three months marking it down. The lowest Kalshi close of the season was 9% on June 25, the night Boston won the first game of the Yankees sweep. Even after the sweep, the contract was only 14% on July 2. The market moved with the streak rather than ahead of it: Boston was 61% with 14 straight wins behind it, and the price did not pass 90% until early August.
Once it got there, it stayed. The contract stayed above 80% every day after August 4 and closed at 94% or higher every day from August 25 on. Polymarket's contract, much thinner at about $5.9K traded, tracked Kalshi within a few points on most days and closed at 100% from September 7 on, two weeks before the clinch.
As the No. 5 seed, Boston opened the AL Wild Card Series at Yankee Stadium and was swept, losing 9-0 on September 29 and 9-2 on September 30. New York then lost the AL Division Series to Tampa Bay in three games.
The Rays now meet Cleveland in an AL Championship Series that was tied 1-1 going into Game 3 on October 15, priced on the 2026 AL pennant market; the winner advances to a World Series settled on the 2026 World Series market. The resolved 2026 AL East market covers the division Boston finished third in, and the Yankees 2026 playoff market covers the team that ended Boston's season. The resolved White Sox 2026 playoff market covers the third AL wild card, and the Boston Red Sox hub gathers every open Red Sox board.
Resolved Yes if the Boston Red Sox qualified for the 2026 MLB postseason, the 12-team field of three division winners and three wild cards in each league, and No otherwise. Kalshi's contract asked whether Boston would be one of the 2026 playoff qualifiers. Polymarket's contract resolved Yes once the team clinched a postseason spot under MLB rules, No if it became mathematically eliminated, and No if the playoffs were cancelled, pushed past October 31, 2026, or the full 12-team field was not confirmed by then; it excluded any tiebreaker game from the playoffs. MLB no longer plays tiebreaker games, so ties for a berth are settled by its tiebreaker formula. Postseason results after qualifying did not affect the contract. Kalshi settled the contract Yes at 5:49 p.m. ET on September 20, 2026, after Boston clinched that afternoon, and Polymarket closed it at 9:25 p.m. ET the same night and resolved it Yes.
Yes. The Boston Red Sox finished 87-75 as the second American League wild card and clinched their berth on September 20, 2026.
Kalshi settled Boston Yes at 5:49 p.m. ET on September 20, 2026, shortly after Atlanta beat Houston. Polymarket closed its contract at 9:25 p.m. ET the same night and resolved it Yes.
Kalshi had Boston at 99% at the close on September 19, the night before the clinch, and 91% on August 20. The same contract was 11% on June 18 and closed as low as 9% on June 25.
A 58-32 finish after a 29-43 start, built on a 15-game winning streak from July 3 to 22 and a 21-4 July. The clinch came on September 20 when Houston lost to Atlanta, capping the Astros below Boston's guaranteed win total.
Boston was swept by the Yankees in the AL Wild Card Series, 9-0 on September 29 and 9-2 on September 30. The AL pennant and World Series markets price the rest of the postseason.