A few days ago, Polymarket quietly changed a rule without any announcement.

The 500ms taker delay in the crypto market was removed. Previously, each order had a half-second waiting period, allowing market-making bots to cancel quotes during this half-second, effectively acting as a free safety net. Now, orders are filled instantly, and if the quote is 200ms slower, it gets canceled.

Many market-making bots have started losing money.

Many people might have seen this account—total profit of $680K, over 16,000 trades. After the rule change, it also experienced a loss but recovered after a few days. I pulled its on-chain data and found some interesting things.

It holds both Up and Down positions in 26 out of 40 markets simultaneously. The average buy-in price for Up is 0.60, for Down is 0.39, with a combined cost of 0.99. Both sides will definitely pay out 1.0 at expiration, so a 0.01 difference is profit.

In simple terms, it’s not betting on the direction. It’s standing on both sides, earning from the bid-ask spread.

The trading frequency is about 1.6 seconds per trade. The last 100 trades are all buys, with zero sells. Within 18 minutes, 500 trades were completed across BTC, ETH, SOL, and XRP markets with 5-minute and 15-minute timeframes. Each trade yields less than 1% profit, accumulated through high frequency.

The rules for predicting markets are still changing frequently, and adaptability might be more valuable than the strategy itself.

Account analyzed in this article: