Maine's Republican Senate contract leaps, but its Democratic twin disagrees

+29 points in a day puts the Republican outcome at 64%, beside a Democratic twin priced at 63%.

In one line: The Republican contract at 64% and its Democratic twin at 63% cannot both be right; the 29-point single-day move looks like the less reliable price.

Kalshi's contract on Maine's Senate race paying on a Republican win jumped 29 points in the 24 hours to 28 September, to 64%. It pays only if Graham Platner is the Democratic nominee and a Republican then takes the seat. It traded at 32% on 21 September. The single-day leap took it to its seven-day high and left it up 32 points over the week.

The other contract in the event asks the mirror question. It pays if Platner is the nominee and a Democrat wins, and it trades at 63%. Both contracts need Platner on the ballot, and only one party can win, so at most one of them can pay. Yet traders now price each outcome as more likely than not.

A fall in the Democratic contract below 36% would make the Republican price right. Only one party can win, so the two prices can add up to 100% at most, and 64% leaves 36% for the Democrats. The best case for the move is that the Democratic contract has not yet updated and will fall to match it.

The Republican contract at 64% overstates the party's chance if the Democratic twin at 63% is the better-anchored price. The Democratic contract still below the Republican one on 5 October would be an early sign against this call, and a Republican declared the winner in November's vote would settle it the other way.