Commission-free trading is one of the most successful marketing phrases in modern finance. Nobody pays a visible fee per trade anymore, and that is precisely the point. The cost did not disappear. It moved somewhere harder to see.
Where the money actually goes
Most zero-commission brokers earn revenue through payment for order flow. Instead of routing your order to an exchange directly, the broker sells it to a market maker, which executes the trade and pockets a slice of the spread. The practice is legal in the United States and disclosed in the fine print, but the SEC has repeatedly examined whether it creates a conflict between the broker’s revenue and the customer’s execution price. You do not see a line item for it. You feel it in the price you get.
The effect on a single small trade is tiny, often a fraction of a cent per share. Across millions of orders it funds entire companies. That should tell you something about who is really paying.
Crypto is where the gap widens
Stock orders at least trade on regulated exchanges with public quotes. Crypto on commission-free apps is a different story. Most apps quote you a price that already includes a markup or spread over the market rate, and the size of that spread is rarely published anywhere. Buy and sell the same coin within a minute and the round trip cost becomes obvious.
Independent breakdowns are more useful than official fee pages here, because the official pages tend to say “zero commission” and stop. For a concrete example of how spread-based pricing works in practice on a popular app, Cryptsy’s Robinhood crypto fee guide walks through where the costs sit and how to estimate what a trade really costs before you place it.
Other quiet drains worth checking
- Withdrawal and transfer fees. Moving coins off an app to your own wallet often carries a network fee plus a platform charge on top.
- Cash sweep interest. Idle cash in your account earns the broker more than it earns you unless you opt into a sweep program.
- Margin and instant deposit charges. The free tier is free. The convenient tier is not.
- Currency conversion. Non-USD deposits usually pass through a conversion step with its own spread.
How to protect yourself
Treat “free” as a claim about commissions only, never about total cost. Compare the quoted price against a live market price before confirming any crypto trade. Check what a full round trip costs on a small test amount before committing serious money. And read the revenue section of your broker’s disclosures once. It is dry reading, but it answers the only question that matters: if you are not paying them, who is?