Commission-free trading killed the visible fee and multiplied the invisible ones. Knowing where brokers actually earn lets you compare platforms on the numbers that matter — total cost of ownership.
How Zero-Commission Brokers Earn
Payment for order flow (PFOF): market makers pay brokers for retail orders and earn the spread — your 'free' trade costs a fraction of a cent of price improvement, trivial for small occasional orders, meaningful at volume. Plus: net interest on your idle cash (often the biggest line), securities lending of your shares, margin interest, and premium subscriptions. Free is a business model, not a gift.
The Fees That Actually Hurt
FX conversion (0.5-1.5% at some brokers every time you trade foreign-currency assets) quietly dominates costs for international investors — multi-currency accounts (IBKR, Saxo) fix it. Margin rates range from ~5% to 12%+ across brokers for identical loans. Inactivity fees, transfer-out fees, and wide spreads on exotic instruments round out the traps. Every one of these is comparable in advance.
Comparing Brokers Honestly
Model your actual usage: trades per month, average size, currencies, margin use, cash balances. A buy-and-hold ETF investor optimizes for FX and custody costs; an options trader for per-contract fees; a cash-heavy account for interest paid on idle balances. Our platform reviews price these scenarios explicitly rather than repeating 'commission-free' marketing.
Frequently Asked Questions
Is PFOF bad for me?
At retail size the measured cost is small, and US brokers must seek best execution. At high volume, direct-routing brokers (IBKR Pro) offer measurably better fills.
What's the most overlooked fee?
Currency conversion — routinely 100x the explicit commission on international trades — followed by forgone interest on uninvested cash.