Prediction platform Polymarket has rolled out five-minute crypto up-or-down betting contracts on its regulated U.S. platform. Operated by QCX LLC, the platform runs under Commodity Futures Trading Commission (CFTC) oversight.
Traders can bet on whether a cryptocurrency will end a five-minute period above or below its starting price, allowing investors to capitalize on ultra-short-term price movements in bitcoin BTC, ether ETH, solana (SOL) and XRP (XRP). Even a small price change can determine whether a contract pays out.
The structure is similar to binary options, which have long been traded in traditional financial markets. Unlike conventional options, where returns can vary with the size of a price movement, binary options offer an all-or-nothing outcome.
That distinction is key because the payout depends on which side of a price threshold the market finishes, rather than how far the underlying asset moves.
For traders, the binary plays introduced Oct. 28 eliminate the need to time precise exit points or calculate complex percentage gains. The payoff structure is simple enough for even a novice user to grasp: A correct prediction yields a fixed $1 payout per share, an incorrect one pays nothing. By lowering the barrier to entry, the options effectively democratize access to short-term derivative trading.
Mati Greenspan, market analyst and CEO of Quantum Economics, said the apparent simplicity conceals risks.
“A button marked ‘up’ or ‘down’ makes the decision look simple. It tells you nothing about the sophistication of your competition,” Greenspan told CoinDesk.
The contracts are finding a market beyond crypto platforms. Kalshi recorded more than $1 billion in crypto event-contract trading in March 2026, according to a research paper published by ArXiv. Nasdaq and Cboe have also considered offering similar products.
Flagging settlement risks
A working paper published on arXiv on June 30 examined Polymarket’s earlier five-minute bitcoin contracts, which debuted in February. The study analyzed trading activity from their introduction through roughly April and found a sharp increase in bitcoin trading just before expiry.
In some cases, prices, leading researchers to suspect that traders were buying or selling bitcoin to influence the outcome of their bets. Those findings predate Polymarket’s August 2026 change to time-weighted average price (TWAP) settlement and do not apply to the new U.S. products.
For the older products, the researchers also found that bitcoin spot order flow increased by roughly 50% during the final 10 seconds of the contracts. When the settlement outcome was close, they also observed sharp price movements followed by reversals, again raising questions about whether traders were attempting to influence the result.
The study identified 821 wallets associated with settlement periods that researchers classified as manipulated and estimated $8.2 million in profits linked to those trading patterns. It also estimated that retail traders accounted for 93% of the corresponding losses. The analysis does not establish the intentions of individual traders.
A potential conflict arises when a trader holding a large Polymarket position could profit by buying or selling the underlying cryptocurrency to influence the price used to settle the bet.
“If influencing the settlement price costs less than the additional payout it unlocks, the contract has put a bounty on the closing price,” said Greenspan.
Iliya Kalchev, an analyst at Nexo, said the risk is greatest when the market price is already close to the level that determines whether a contract pays out. In that situation, even a small price move could change the outcome of many bets.
“Ultimately, whether manipulation could be profitable depends on the potential payout relative to the cost and risk of influencing the underlying market, rather than open interest alone,” Kalchev said.
Polymarket did not respond to a CoinDesk request for comments.
Is prevention possible?
Polymarket’s U.S. platform settles its markets using CF Benchmarks real-time dollar indexes, calculating the average of 60 index observations recorded during the final 60 seconds of the window. Globally, the platform utilizes Chainlink’s 60-second time-weighted average price (TWAP) to determine expiry.
The platform revised its settlement rules in August due to the concerns about traders exploiting short-lived price movements.
The change is important when comparing the new contracts with those examined in the July research. Averaging prices over a minute makes it harder to influence the outcome with a brief trade immediately before expiry, although it does not eliminate the possibility of sustained price pressure.
“A 60-second average can blunt a last-second spike. It’s a speed bump, not a force field,” Greenspan said.
Kalchev said that averaging prices over a minute makes manipulation more expensive because a trader would have to keep the price elevated or depressed for longer, potentially while other traders buy or sell against the move.
“Bitcoin is harder to manipulate because it is more liquid,” Kalchev said. “Smaller cryptocurrencies, particularly during quieter weekend trading, may be more vulnerable.”
Kalchev said market makers could respond by increasing the gap between buying and selling prices, accepting smaller trades or pulling their orders as contracts near expiry. That would raise the cost of placing large bets, although traders could still have an incentive to move prices in their favor.
Regulatory scrutiny
The U.S. introduction comes as Polymarket faces renewed scrutiny over its operations, although regulators have not alleged manipulation of the new five-minute markets.
The Commodity Futures Trading Commission (CFTC) is investigating whether the company violated a 2022 settlement requiring it to block U.S. users from its offshore platform, Reuters reported Tuesday. The regulator is also examining customer protections and onboarding procedures on the company’s U.S. platform, the report said. Neither the CFTC nor Polymarket commented.
In August, the CFTC warned prediction-market operators about compliance failures involving trading incentives and market abuse.
Greenspan said the risk would grow if the contracts attracted enough money to make influencing settlement prices worthwhile, particularly in less liquid cryptocurrencies.
Neither Greenspan nor Kalchev have seen evidence that the newly launched U.S. contracts have moved spot cryptocurrency prices.
Originally published at https://www.coindesk.com/markets/2026/10/29/polymarket-brings-ultra-short-crypto-prediction-markets-to-u-s-platform.
