Fees and Net Returns in Copy Trading

Your net return is gross profit minus subscription, trading fees, slippage, and transfer or gas costs. A leader's 40 percent gross return can become a fraction of that in your account, and a 5 percent edge can disappear entirely. The leaderboard shows what the leader earned before your costs, at the leader's size, in the leader's fee tier.

Fees are certain. Returns are not. That asymmetry is why the cost stack deserves more attention than the return forecast.

The cost stack

There are five layers, and they compound:

1. Subscription or performance fees paid to the platform or the leader.
2. Exchange trading fees, which on Polymarket depend on the market category and whether you take or make liquidity.
3. Spread and slippage, the difference between the price you see and the price you get.
4. Transfer, bridge or gas costs when money moves between wallets or chains.
5. Taxes, which are not a fee but reduce the net result.

A copy strategy can pay all five. A manual strategy usually pays three. The difference is not automatically fatal, but it has to be measured.

Polymarket's trading fee

Polymarket charges a taker fee on certain markets. The formula is shares multiplied by the fee rate multiplied by price multiplied by one minus price. Makers are never charged. The rate depends on the category: 0.04 for Politics, Finance, Mentions and Tech; 0.05 for Sports, Economics, Culture, Weather and Other; 0.07 for Crypto; and zero for Geopolitical markets. Combos have their own rate.

Because the formula includes price times one minus price, the dollar fee for a fixed number of shares peaks at a price of $0.50 and falls toward both extremes. But the fee as a percentage of the dollars you pay behaves differently. At $0.20, 1,000 shares cost $200 and the Politics fee is $6.40, or 3.2 percent. At $0.50, the same 1,000 shares cost $500 and the fee is $10.00, or 2.0 percent. At $0.80, they cost $800 and the fee is $6.40, or 0.8 percent.

Cheap longshots therefore carry a higher fee relative to the stake. As the price approaches zero, the fee approaches 4 percent of the amount paid in a Politics market. That matters for copy strategies that specialize in low-priced tails.

Polymarket does not charge its own fee to deposit or withdraw USDC, though intermediaries such as Coinbase or MoonPay may charge their own. Trading wallet operations can be sponsored through Polymarket's relayer, but moving funds across chains can still involve network or provider costs.

Subscription and performance fees

Subscription fees are platform-specific, so read the actual schedule rather than assuming. A 1 percent annual fee on a $10,000 account is $100. A 20 percent performance fee on $2,000 of profit is $400. If a product charges both, the combined drag can exceed the trading fees.

Ask three questions. Is the performance fee charged on realized profit only, or on mark-to-market gains? Is there a high-water mark, so you do not pay twice to recover the same loss? And is the leader compensated from your subscription, which creates an incentive to attract followers rather than to trade well? IOSCO flags the remuneration structure between platforms, leaders and followers as a source of conflicts.

From gross to net

A worked example: from gross to net

Take a $10,000 account running 60 round trips a year, with an average position of $500 in a Politics market at $0.50. Assume taker orders on both sides and no maker rebates.

Each $500 position is 1,000 shares. The fee is $10 per side, or $20 per round trip. Sixty round trips cost $1,200, or 12 percent of the account.

Assume slippage of half a cent per share per side. That is $5 per side, $10 per round trip, or $600 a year, another 6 percent.

Add a 1 percent subscription: $100, or 1 percent.

Total cost: $1,900, or 19 percent of the starting account.

Now compare gross results. If the strategy earns 25 percent before costs, or $2,500, the net is $600, or 6 percent. If it earns 15 percent, or $1,500, the net is minus $400, or minus 4 percent. Even a 40 percent gross year, or $4,000, nets $2,100, or 21 percent. The cost stack took nearly half of a very good year.

The same account trading half as often, with 30 round trips, would pay about $900 in fees and slippage plus $100 subscription, or roughly 10 percent. Turnover is the largest controllable variable in the stack.

Why gross leaderboard returns are not your returns

A leaderboard profit number is not a cash-flow statement. Polymarket's leaderboard reports profit and loss over a selected window, and the window can be a day, a week, a month or longer. A trader can look spectacular over 30 days and flat over a year. The board may also rank by volume, which is not profit at all.

The number is calculated on the leader's positions and the leader's fills. It does not include your subscription, your slippage, your fee tier or your taxes. It may include open positions marked at the current price, which are not cash until sold or resolved. And the top of any leaderboard is selected after the fact, so it over-represents traders who took risks that happened to pay off during the window.

The leader may also have structural advantages you do not. A market maker can earn rebates and pay no taker fees. A trader in geopolitical markets pays no fee at all. A large account may get better execution or access. Copying the trades without copying the cost structure can turn a leader's edge into your loss.

FINRA Rule 2210 states that communications may not predict or project performance, imply that past performance will recur, or make an exaggerated or unwarranted claim. Treat a leaderboard return the same way: as history, not a promise.

Expectancy after costs

The cleanest way to compare strategies is expected value per trade after costs.

Suppose a strategy wins 55 percent of the time, with an average win of $120 and an average loss of $100 over 100 trades. Gross expected value is 0.55 times $120 minus 0.45 times $100, or $66 minus $45, which is $21 per trade. Over 100 trades, that is $2,100.

Now subtract $10 of trading fees and $5 of slippage per trade, or $15. Net expected value is $6 per trade, or $600 over 100 trades. Costs consumed 71 percent of the gross edge.

If the win rate falls from 55 percent to 52 percent, gross expected value becomes 0.52 times $120 minus 0.48 times $100, or $62.40 minus $48, which is $14.40 per trade. After $15 of costs, the strategy is negative. A three-point change in win rate, well within sampling noise, flips the result. That is how thin margins become losses.

How to reduce the drag

Trade less. The most effective cost control is holding positions longer and copying fewer, higher-conviction trades. Use limit orders when you can; makers pay no fee on Polymarket, though they accept the risk of not filling. Avoid copying very cheap longshots unless the edge is large enough to cover the higher fee percentage. Cap slippage with a maximum price deviation. Size from visible depth. Prefer fee-free or lower-fee categories when the opportunity is comparable. And avoid performance fees without a high-water mark.

Build a cost budget before you copy. If your expected gross edge per trade is 3 percent and your all-in cost is 2 percent, you keep one-third of the edge. If the cost is 2.5 percent, you keep one-sixth. If you do not know the edge, paper trade until you do.

Net return is the only return that pays you. Everything else is a hypothesis with a fee attached.