The MLB season and the World Series
162 games to sort thirty teams, and then a tournament where the best team beats the worst one about six times in ten. Baseball is the sport where the regular season means most and the playoffs mean least.
At a glance
- Teams
- 30, in two leagues of 15
- Regular season
- 162 games, from late March to the end of September
- Playoff field
- 12 teams since 2022; the top two seeds per league receive byes
- Final
- The World Series, best-of-seven, in late October
What the competition actually is
Thirty teams play 162 games across two leagues. Six teams per league reach the playoffs: three division winners and three wild cards. The top two seeds in each league receive a bye through the first round; the remaining four play a best-of-three wild card series, entirely at the higher seed's park.
From there it is a best-of-five division series, a best-of-seven league championship series, and a best-of-seven World Series. Reaching the title from the wild card round takes eleven wins across four series in under a month.
The 2022 expansion from ten teams to twelve changed the shape of the market. More teams qualify, the bye is more valuable, and the best-of-three opening round is short enough that a bye-holding favourite can be eliminated by a team it would beat comfortably over a longer series.
The best team in baseball beats the worst one about six times in ten. Every playoff series starts closer to a coin flip than any other sport.
What the format does to the odds
Baseball's defining statistical property is that single-game outcomes are close to random even between mismatched teams. The best team in a season wins around 60 percent of its games; the worst wins around 40. Compress that into a best-of-three and the favourite's series probability barely clears 60 percent - which is why October results so often contradict the standings.
The consequence for markets is a flat probability distribution. Championship odds spread across ten or more teams, top seeds carry far less advantage than in basketball, and the regular-season leader is frequently not the favourite by much. Anyone importing intuitions from the NBA will systematically overprice the best team.
It also makes the bye unusually valuable. Skipping the best-of-three round removes the format's biggest coin flip, which is worth more here than the equivalent bye is in football. The late-season race for a top-two seed is the single most reliable source of futures movement in September.
1162-game season
Sorts six playoff teams per league
2Wild card series
Best-of-three, all at the higher seed
The shortest series and the biggest coin flip
3Division series
Best-of-five; the top two seeds enter here
4League championship series
Best-of-seven
5World Series
Best-of-seven in late October
The calendar and the official record
The schedule has been balanced since 2023: every team now plays every other team at least once during the season, which reduced the weight of divisional play and made records more comparable across the league. Roughly a third of games are inside the division, a bit under half against the rest of the same league, and the remainder against the other league.
The trade deadline at the end of July is the season's hinge. Unlike leagues with a hard cap, baseball allows a contender to absorb salary and buy a pitching rotation for October, and the market reprices heavily around it. It is also where teams out of contention sell, which reshapes the bottom of the standings.
Settlement rests on the league's official records: standings, tie-breakers - decided by head-to-head record rather than a playoff game since 2022 - and the postseason results. Statistical markets settle on official statistics, which are subject to scoring decisions that can be reviewed after the fact.
- Balanced schedule since 2023: every team plays every other team.
- Trade deadline at the end of July - the largest scheduled repricing of the season.
- Seeding ties are broken by head-to-head record, not a tiebreaker game.
- The top two seeds per league receive a bye through the wild card round.
- Rest of the same league64 games
- 40%
- Division opponents52 games - thirteen against each of four rivals
- 32%
- The other league46 games, including every team at least once
- 28%
Source: MLB scheduling format
Behind the subscription
The rest of this entry is the part that changes a decision: what moves the price, which contract sets it, who ships it and where that can be cut off.
What moves title odds
Six drivers, and the reason this sport's futures market moves less on results than any other: the standings barely constrain October.
Exchange against sportsbook
Why a flat probability distribution makes the sportsbook margin especially expensive here, and what to compare instead.
Where the title probability sits
The seed distribution of champions, and the statistic that captures why baseball futures behave so differently.
How this shows up in prediction markets
Championship, pennant, division and statistical markets - and the rain rule that has settled more baseball contracts than people expect.
Included with a subscription
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Schedule, venues and live odds
Who plays when and where this week, with the live price of every game.
Frequently asked questions
- Why does the best regular-season team so rarely win the World Series?
- Because single baseball games are close to coin flips even between mismatched teams. The best team wins around 60 percent of its games; over a best-of-three or best-of-five, that edge translates into only a modest series advantage, and it has to survive four rounds of it.
- How valuable is the first-round bye?
- More than in any other league, because the round it skips is the shortest and therefore the most random. That is why the September race for a top-two seed moves futures prices more than almost anything else in the baseball calendar.
- Why do longshots price better in baseball than in basketball?
- Because the format compresses differences between teams instead of amplifying them. A marginal playoff team is a genuine title contender here, which is a statement that would be absurd in the NBA - and the historical record of wild card champions bears it out.
- What happens to a market if a game is rained out?
- It depends on the rules of the venue. Games can be suspended and resumed, postponed to a later date, or in rare cases shortened and counted as official. A single-game market that does not address this is a dispute waiting to happen.
Primary sources
Related entries
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