If trades are commission-free, how does the brokerage make money?

Commission-free brokerages typically generate revenue through several channels rather than one, including payment for order flow, interest on uninvested cash, margin lending interest, and premium subscription features.

What is payment for order flow?

Payment for order flow is a practice where a brokerage routes customer orders to a market maker or other trading venue in exchange for compensation, rather than routing directly to a public exchange. It is legal and must be disclosed, but has drawn regulatory attention regarding its effect on execution quality.

Is payment for order flow bad for investors?

It is debated. Proponents argue it allows brokerages to offer commission-free trading while still delivering competitive execution; critics argue it can create an incentive misaligned with getting customers the best possible price. Reviewing a brokerage's execution quality disclosures directly is the most concrete way to assess this for yourself.

How does a brokerage earn money from my cash balance?

Many brokerages hold customers' uninvested cash in interest-bearing arrangements and keep some or all of the interest earned, rather than passing all of it to the customer, which is a legal and disclosed revenue source distinct from any advisory fee.

Do I pay margin interest even if I never touch my margin balance?

No. Margin interest is only charged on the amount actually borrowed against your account. If you never use margin, you are not charged margin interest, regardless of whether the account is technically margin-enabled.

Are premium subscription tiers common at commission-free brokerages?

Yes, many commission-free brokerages offer optional paid tiers with added features like advanced research, higher-tier customer support, or additional order types, generating direct subscription revenue.

Does commission-free mean completely free to use?

Not necessarily. While the visible per-trade commission may be zero, other costs can still apply, such as fees for specific services, margin interest if used, or the indirect cost of execution quality — reviewing the full fee schedule is worth doing regardless.

Where can I see how my brokerage routes my orders?

U.S. brokerages are required to make certain order routing and execution statistics available to customers, often referenced under SEC Rule 606 disclosures, which show where orders are routed and, in aggregate, how they were executed.

Should I avoid brokerages that use payment for order flow?

That is a personal judgment call rather than a fixed rule — payment for order flow is widespread among commission-free brokerages. Focusing on a brokerage's actual execution quality statistics is generally more informative than avoiding the practice outright.

How Commission-Free Brokers Actually Make Money | Imperialpedia

Commission-free trading became widespread only after brokerages found other ways to sustain the business. Understanding these revenue sources — without assuming they are automatically good or bad — is part of a full brokerage evaluation.

Payment for Order Flow

One of the most discussed revenue sources is payment for order flow (PFOF). Instead of routing your order directly to a public exchange, a brokerage may route it to a market maker, which pays the brokerage compensation for that order flow. This practice is legal and disclosed, but it has drawn regulatory scrutiny over whether it could create an incentive that is not always perfectly aligned with securing the best possible execution price for the customer.

PFOF does not automatically mean you receive a worse price. Many brokerages that use it still provide competitive or better-than-quoted execution on average — the way to evaluate this concretely is through a brokerage's published execution quality statistics, not assumptions about the practice alone.

Interest on Uninvested Cash

Brokerages often hold customer cash balances that are not currently invested — money sitting in the account between trades, for example — in interest-bearing arrangements. The brokerage may keep some or all of the interest earned on these balances rather than passing the full amount to the customer. This has become an increasingly significant revenue source, particularly during periods of higher interest rates.

Margin Lending Interest

If a customer borrows against their account through a margin account, the brokerage charges interest on the borrowed amount. This interest is a direct and often substantial revenue source. Importantly, margin interest is only charged on funds actually borrowed — simply having a margin-enabled account without borrowing does not trigger this cost.

Premium Subscriptions and Add-On Services

Many commission-free brokerages offer optional paid tiers, bundling features like advanced charting, in-depth research reports, or extended customer support into a monthly or annual subscription. This is a straightforward, transparent revenue stream that does not depend on trading activity.

A Neutral Comparison

Revenue Source	How It Works	Directly Tied to Your Trading?
Payment for order flow	Compensation for routing your order	Yes, per trade
Cash balance interest	Interest earned on your uninvested cash	Indirectly, based on balance
Margin lending interest	Interest on borrowed funds	Only if you use margin
Premium subscriptions	Optional paid feature tier	No, opt-in only

How to Evaluate This as an Investor

None of these revenue models are inherently harmful — every brokerage needs a sustainable business model. What matters is transparency: a brokerage should clearly disclose its order routing practices and be willing to share execution quality data. See our guide on order execution quality for how to interpret this data directly, rather than relying on assumptions about a business model.

Common Mistakes to Avoid

Assuming "commission-free" means there are no revenue sources tied to your account at all.
Avoiding a brokerage based on PFOF alone without checking its actual execution quality statistics.
Overlooking cash balance interest policies, which can matter significantly for large uninvested balances.
Not reading the terms for margin interest rates before enabling a margin account.

Conclusion

Commission-free brokerages are still businesses that need revenue — understanding where that revenue comes from helps you evaluate a brokerage on transparency and disclosure rather than the absence of a visible per-trade fee alone.