“5 minute crypto up/downs are now live in the Polymarket US app,” Polymarket said in its announcement.
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The U.S. venue is operated by QCX LLC, doing business as Polymarket US, a Commodity Futures Trading Commission-regulated designated contract market. It is separate from Polymarket’s international blockchain-based product: U.S. trading is denominated in dollars.
Averages Determine the Winner
The five-minute contracts compare reference prices at the window’s start and finish, not individual spot-market trades. The bitcoin contract’s rules use CF Benchmarks’ Bitcoin Real-Time Index. Ether, solana and $XRP use the provider’s corresponding dollar real-time indices.
At each endpoint, Polymarket averages 60 index observations collected during the preceding minute. Bitcoin and ether values are rounded to two decimal places, solana to four and $XRP to five. If the closing value equals or exceeds the opening value, Up wins; otherwise Down wins.
That averaging mechanism resembles Kalshi’s 15-minute contracts, which compare the index average from the minute before closing with the average from the minute before opening. A shorter contract therefore does not mean settlement depends on a single price tick.
Polymarket’s fee schedule charges liquidity-taking orders using a price-dependent formula: 0.0695 multiplied by the number of contracts, the contract price and one minus that price. Its published example for 100 contracts at 50 cents is a $1.74 taker fee, before any volume-tier rebate. The four five-minute contracts each carry that same fee coefficient in their API terms.
For comparison, Kalshi’s standard schedule lists taker fees of $0.07 to $1.75 per 100 contracts for most markets, with separate exceptions. Those direct-exchange rates should not be read as Coinbase’s customer pricing: Coinbase says its order confirmation screen displays the fee breakdown before submission.
Execution prices matter separately from fees. Polymarket’s API publishes distinct best bid and ask quotes for the new contracts, so the cost of entering and immediately exiting also depends on the spread. Coinbase’s settlement guidance likewise makes clear that the displayed spot price is not decisive: Kalshi determines the official outcome, and Coinbase cannot manually override it.
