Baseball Game Books 2026 — MLB, KBO and NPB

Tonight's anchor is Philadelphia–Washington, and the money is on the wrong side of it. Philadelphia is 64% and took $197,713; Washington at 37% took $262,926. The underdog out-traded the favourite by $65,213 on a board turning $460,280, and holds only $61,673 of open interest against Philadelphia's $195,818—so the Washington money is flow, not position.

The title board does the same thing at a longer horizon. Kalshi's championship market turns $676,686 in a day. The price leader, Los Angeles D at 32.5%, took $75,552—but Cleveland at 2.3% took $65,838 and Houston at 3.4% took $62,236, second and third on the board. $128,074 went to two teams the market gives a combined 5.7% chance, against $55,318 for second-priced Milwaukee at 15.8%.

The playoff qualifier board is the exception that explains the rule. It turns $263,622, and its busiest legs are Philadelphia at 93% ($22,668), San Diego at 81% and Chicago WS at 84%—the three teams still genuinely in doubt. Six clubs sit at 99% and traded nothing at all. When a board has real uncertainty in the middle, the money goes to the middle.

And the runs ladder is a single strike. Over 7.5 runs in Chicago WS–Cleveland is 48% and has taken $69,774 of that board's $119,500—58% on the one rung that is a coin flip.

Kalshi's championship board is the deepest baseball market on any exchange—$676,686 in a day against more than 20 million contracts of standing open interest. Polymarket books the same question below.

Left: Los Angeles D at 32.5%, the price leader, holding 2,711,957 contracts of open interest and taking $75,552 on the day. Right: Cleveland at 2.3%, which took $65,838.

A team priced at one fourteenth of the favourite traded within nine thousand dollars of it. That ordering has held on this board all month.

The Korean league books settle in the small hours; beside them, Kalshi's playoff qualifier market, which is the only board on this page whose money follows its uncertainty.

Below: the Chicago WS–Cleveland total-runs ladder, where $69,774 of $119,500 sits on the single 48% rung at Over 7.5. The twenty rungs around it share the rest.

Tomorrow's Kiwoom Heroes–Kia Tigers board, both sides. Kalshi's KBO coverage runs thin outside the marquee fixture—these books open on a market maker's marks and often settle with only a few hundred dollars traded against them, which is the cleanest available read on how much real liquidity the league carries here.

The concentration is the story on all three horizons, and it inverts where the uncertainty is. On the title board, $128,074 went to Cleveland and Houston at a combined 5.7%. On tonight's game book, the 37% underdog out-traded the 64% favourite by $65,213. On the runs ladder, 58% of the money went to the one rung priced at a coin flip.

The qualifier board is the control case. It is the only market here whose busiest legs are its most uncertain ones—Philadelphia at 93%, San Diego at 81%, Chicago WS at 84%—while six clubs at 99% traded nothing. Cheap-leg buying is not universal; it shows up when the board has already decided and the only thing left to buy is a lottery ticket.

Watch whether Washington's flow turns into position. It has taken $65,000 more than Philadelphia and holds a third of the open interest. If that gap closes before first pitch, the money was hedging; if it widens, somebody genuinely likes the Nationals tonight.