Someone went through more than 800 active wallets on Polymarket, and in the end only a handful are truly worth continuing to track.

Among the high-profit accounts that make up over 40%, their edge comes from the order-book placement and the bid-ask spread on both sides, with little to do with predicting the outcome.

In the same market, YES and NO together will ultimately be paid out $1. Market-making accounts place low-priced limit orders on both sides in advance: as long as both sides get filled and the total cost is below $1, they can take the middle spread at settlement.

But sometimes only one side gets filled. In that case, the account still effectively bets on the result, and if the price moves the opposite way, it will lose—so if others just look at win rate and cumulative profit, it’s hard to tell whether it’s market making or one-sided betting.

There are also many accounts whose profits are driven mainly by a single trade. For more than half of the wallets, over 40% of their profits come from the same market. After nailing it once, the entire profit curve can start looking very good.

He also calculated what happens when copy-trading is delayed by a few minutes, a few hours, or a full day. If a market only settles after a few days, being an hour late can sometimes still get a close price—but sports markets and contracts that settle quickly don’t.

By the time public trades appear, the price may have already moved through the relevant range, and market-makers’ limit orders placed ahead of them on the order book can’t be replicated.