Polymarket Fees and Taxes: How Taker Fees Change Your Gain or Loss

Polymarket fees matter for taxes because they lower your real profit, but the way they lower it depends on the tax treatment you and your preparer use. Under capital-asset treatment, a taker fee is added to your cost basis when you buy and subtracted from your proceeds when you sell. Under gambling treatment, fees count as part of your wagering losses, which from 2026 are only 90% deductible. Under "other income," you simply report the net after fees.

OddsFile is software, not tax advice. The IRS has not issued guidance on how prediction-market contracts are taxed. This article explains the options and sources; a tax professional can tell you which position fits your situation.

How Polymarket fees work in 2026

Polymarket's fee documentation describes a taker-only model:

• Makers pay nothing. Only the side that takes liquidity pays.
• Formula: fee = shares × fee rate × p × (1 − p), where p is the share price. The fee peaks at 50 cents and shrinks toward 0 and 1, so a 30-cent trade and a 70-cent trade pay the same dollar fee.
• Category rates: the docs list rates such as 0.07 for crypto, 0.05 for sports, and 0.04 for politics and finance. Geopolitics and world-event markets are fee-free.
• Currency: fees are charged in USDC. Deposits and withdrawals carry no Polymarket fee, though on-ramps such as Coinbase or MoonPay may charge their own.

Rates have changed more than once in 2026, so treat the table in the docs as the source of truth for any given trade date, not a number you remember.

Finding the fee in your own data

You don't need to recompute the formula. In Polymarket's activity data, each trade shows the USDC you paid (usdcSize), the shares (size) and the price. The difference is the fee:

fee = usdcSize − size × price

When we tested this against Polymarket's own position data, the computed fees matched the platform's entryFeesUsdc field to the cent. That is how OddsFile attaches a fee to every fill.

Worked example: one market, three treatments

Assume you buy 1,000 YES shares in a crypto market at $0.40, sell 400 of them at $0.70 before resolution, and hold the other 600 to a $1.00 payout.

Fees (crypto rate 0.07):

• Buy: 1,000 × 0.07 × 0.40 × 0.60 = $16.80
• Sell: 400 × 0.07 × 0.70 × 0.30 = $5.88
• Redemption at resolution: no trading fee.

Cash flows:

• Cost: $400.00 + $16.80 = $416.80, or $0.4168 per share.
• Sale: 400 × $0.70 = $280.00 − $5.88 = $274.12 net proceeds.
• Redemption: 600 × $1.00 = $600.00.

Profit after fees: $274.12 + $600.00 − $416.80 = $457.32. Without fees it would have been $480.00, so fees cost $22.68.

Under capital treatment the 1,000-share lot is split: 400 shares carry $166.72 of basis and 600 shares carry $250.08. This is the same arithmetic the IRS expects for any property: basis includes acquisition costs, and the amount realized is reduced by selling expenses (Form 8949 instructions).

Are Polymarket fees tax deductible?

Not as a separate line item in most cases. Fees aren't an itemized deduction for an individual investor; they reduce the gain on the trade they belong to. The practical answer by treatment:

• Capital: fees are "deductible" in the sense that they shrink each gain or enlarge each loss. Net capital losses then face the $3,000 annual limit (IRC §1211(b)).
• Gambling: amended IRC §165(d) treats expenses of wagering as wagering losses, and for tax years starting in 2026 only 90% of those losses are deductible, capped at winnings, and only on Schedule A. See the 90% loss limit explained.
• Other income: you report the net, so fees are already inside the number.

For the bigger picture on which treatment people use and why, read gambling vs capital gains for event contracts.

Gas, bridging and on-ramp fees

Polymarket trading is gasless for most users, but money still moves on-chain:

• Bridging or withdrawing USDC may cost network fees. Moving USDC between your own wallets isn't a sale, but paying a fee in a token is technically a disposal of that token. With USDC near $1, the gain or loss is usually close to zero.
• On-ramp fees (card purchase of USDC) are generally part of the USDC's basis.
• Withdrawal fees paid when leaving a position are generally selling expenses.

These amounts are usually small, but on wallets with hundreds of transfers they add up, and they are a common reason a self-built spreadsheet doesn't tie out to the wallet balance. Our multiple-wallets guide covers transfers in more detail.

Maker rebates and rewards

Polymarket pays maker rebates and liquidity rewards. These are not reductions of a specific trade's fee; they are receipts. Many preparers report crypto rewards as ordinary income at fair market value when received (IRS digital assets; Rev. Rul. 2019-24 covers airdrops, not rebates, so this is by analogy). Keep them separate from trading results so the treatment choice for contracts doesn't swallow them.

Records to keep

• The activity export for every wallet, including fees per fill.
• The fee rate in effect on the trade date if you recompute anything.
• On-chain transaction hashes for bridges and withdrawals.
• A note of which treatment your return uses, so fees land in the same place every year.

Run the free OddsFile check: paste a Polymarket address and see fees, per-market P&L, and your result under each treatment, no signup.

FAQ

Does Polymarket charge a fee on winnings?

No. Polymarket's documented fees apply to taker trades. Redeeming a winning position at resolution isn't a taker trade, so there's no trading fee on the payout itself.

Are Polymarket fees tax deductible on their own?

Generally no. They adjust the gain or loss on the trade they relate to. Under gambling treatment they are wagering losses, subject to the 90% limit from 2026 and itemizing.

Why doesn't my profit match Polymarket's P&L display?

Common reasons: fees, losing positions that were never redeemed, and transfers between wallets. See unredeemed losing positions.

Do maker rebates count as income?

Most preparers treat rebates and rewards as income when received. There is no IRS guidance specific to Polymarket rebates; ask your preparer.

Does Polymarket send a 1099 showing fees?

The international exchange has historically not issued 1099s. See does Polymarket send a 1099 and the full Polymarket taxes guide.