Backing Polymarket’s primary favorites would have lost 4%, new audit finds.

A hypothetical strategy of backing the favorite on prediction market Polymarket in every scored 2026 US primary would have lost 4%, even though those candidates won 87% of the time, according to blockchain data provider Bitquery’s scorecard dated Oct. 9. The result separates two questions for election bettors: who is most likely to win, and whether their contract is worth the price.Bitquery found that the candidate with the highest study reference price won 238 of 273 Senate, House and governor primaries. But its hypothetical strategy of putting $1 on each favorite at the study’s reference price lost four cents per dollar.The strongest favorites did much of the work behind the headline accuracy rate. Candidates priced at 90 cents or more won 177 of 182 races. Among favorites priced between 50 and 90 cents, however, 71% won despite an average price of 77 cents.An outcome share pays $1 when it wins and nothing when it loses. Buying an expensive favorite therefore leaves little profit on a winning share, while a losing share wipes out its purchase cost. Enough losses can outweigh many correct calls.Putting the same dollar amount into every race also buys different numbers of shares. A...