Commission-free brokerage changed the price investors saw before placing a trade. It did not remove the economics behind the transaction. Brokers still needed revenue, and payment for order flow became one way to earn it: trading firms paid brokers to send customer orders to them for execution.
The history is therefore about two connected developments, not one invention. Trading commissions fell as brokers competed for customers. Meanwhile, customer orders became a source of revenue in their own right. Their convergence made small investments cheaper to place, but also raised a persistent question: was the broker choosing the best destination for the customer, or the most profitable destination for itself?
From Discount Commissions to Zero
The earlier turning point came on May 1, 1975, when fixed brokerage commissions ended on US securities exchanges. Brokers gained room to compete on transaction prices rather than follow prescribed minimum charges. The end of fixed US brokerage commissions established the competitive setting in which discount brokerage developed.
Discounting and commission-free trading solve different pricing problems. A discount broker charges less for executing a transaction, often separating that service from personalized advice. A commission-free broker removes the explicit commission on eligible transactions and earns revenue elsewhere. Neither description, by itself, establishes the quality of the service.
Consider a hypothetical investor buying $100 of stock each month. A $5 purchase commission consumes 5% of each contribution before the investment has earned anything. Removing that charge makes small, regular purchases more practical. For someone placing a $50,000 order, the same $5 charge represents a much smaller hurdle.
This arithmetic explains why zero commissions mattered beyond advertising. The benefit depended on the investor’s trade size and habits, rather than simply the number printed on a broker’s pricing page.
Payment for Order Flow Predated Trading Apps
Payment for order flow, usually shortened to PFOF, was already a regulatory issue long before smartphone brokerage. In 1994, the SEC required brokers to disclose on customer confirmations whether they received such payments. Its December 2000 study of options order routing examined cash payments and other incentives offered to firms directing customer trades.
That study captured an early version of the later controversy. As options exchanges competed for orders, payments became another way to attract business. SEC staff found that firms accepting payments moved orders to paying specialists more frequently than firms maintaining policies against accepting them.
The historical distinction matters. Commission-free apps did not invent the commercial value of customer orders. They helped turn an existing source of brokerage revenue into support for a more visible pricing proposition.
Nor did PFOF automatically replace commissions dollar for dollar. The two could coexist. A broker could charge customers for transactions while also receiving compensation connected with their routing. Zero commissions changed how the benefits and costs of that arrangement needed to be assessed.
The 2019 Shift to Commission-Free Brokerage
Robinhood brought commission-free stock trading to a mobile audience during the mid-2010s. The broader pricing shift followed in 2019, when major established brokers moved to eliminate commissions on eligible online trades. Charles Schwab’s October 1, 2019 announcement was a prominent moment in that transition. The Federal Reserve’s November 2021 review of retail trading connects the removal of commissions with the preceding growth of order-flow revenue.
The commercial question changed. Instead of asking how much revenue each trade could produce through a commission, a firm could assess the revenue available from the wider account relationship.
That distinction also prevents an overly simple reading of the price war. Brokers could advertise the same zero commission while operating different businesses. One might rely more heavily on trading activity; another might place greater value on cash balances, borrowing or paid services.
The transition extended the price competition associated with the rise of discount stock brokers, but introduced a harder comparison. A commission is easy to see. The economic consequences of an order-routing arrangement are not.
How Payment for Order Flow Works
In a common US stock-trading arrangement, an investor submits an order to a retail broker. The broker sends it to a wholesale market maker, which may execute the trade against its own account rather than send it to a public exchange. The wholesaler pays the broker for the order flow.
The wholesaler values the opportunity to trade against those orders. Retail flow can present less risk of trading against better-informed counterparties than some institutional flow. That can leave room for the wholesaler to offer a favorable execution price, pay the broker and still expect a profit. The Congressional Research Service report on payment for order flow describes this business model and its competing incentives.
Several distinctions matter. The broker’s routing payment is not the same thing as the bid–ask spread. Nor is it necessarily a separate charge deducted from the customer’s account. Its possible cost to the customer is more often a question of execution quality: could the order have received better terms elsewhere?
Stock and options routing should not be treated as identical. The CRS report distinguishes stock orders executed internally by wholesalers from listed options orders, which generally go to options exchanges.
A Hypothetical Execution Example
Suppose the best displayed bid for a stock is $49.98 and the best displayed offer is $50.00. An investor wants to buy 100 shares. The following prices are illustrative, not observations from an actual broker.
| Execution outcome | Purchase price per share | Total purchase cost | Saving against the displayed offer |
|---|---|---|---|
| Execution at the displayed offer | $50.000 | $5,000.00 | $0.00 |
| Execution with modest price improvement | $49.995 | $4,999.50 | $0.50 |
| Execution with greater price improvement | $49.990 | $4,999.00 | $1.00 |
Both improved prices beat the displayed offer. Yet one saves the investor another 50 cents. Receiving price improvement therefore does not answer whether another available destination could have provided a better result.
The reverse is also true: receiving a routing payment does not, by itself, prove that an order received a worse price. A fair comparison needs evidence about achievable execution outcomes, not just knowledge of who paid whom.
How Brokers Earn Revenue Without Commissions
PFOF is one funding mechanism, not a complete explanation of commission-free brokerage. Margin interest and paid services can also generate revenue. An October 2020 congressional review of Robinhood’s business model identified interest on margin loans and charges for professional research alongside order-flow payments.
These revenue sources reward different customer behavior. Routing income depends on trading activity and the applicable payment arrangements. Margin income depends on borrowing. A subscription can produce revenue even when the customer places no trades.
This creates a useful distinction between removing a charge and removing a conflict. Eliminating commissions removes the direct commission earned from each eligible trade. It does not necessarily remove every financial reason for a broker to encourage activity or promote another paid product.
Cash deserves attention too. Uninvested balances may remain with the investment firm or move into a bank or money market fund through a sweep arrangement. Rates and conditions differ, and a default option is not necessarily the most rewarding one. The SEC’s investor bulletin on cash sweep programs sets out these differences.
For a hypothetical account holding $10,000 in cash for a full year, a two percentage point difference in annual yield amounts to roughly $200 before compounding. That comparison does not establish which cash product is suitable; risks, access and protection also matter. It does show why transaction commissions alone cannot describe the cost of an account.
The Conflict Between Routing Revenue and Best Execution
The central conflict is straightforward. Customers want favorable trading terms. Brokers receiving PFOF also have an interest in the payments attached to routing decisions. Those interests can align, but they should not be assumed to align.
Under FINRA Rule 5310, firms must use reasonable diligence to find the best market and obtain a price as favorable as possible under prevailing conditions. Payment arrangements cannot displace that obligation. FINRA’s guidance on best execution and PFOF also makes clear that obtaining the best displayed bid or offer may not be enough.
Execution quality involves more than a single price comparison. Relevant considerations include opportunities for price improvement, speed, execution size and the likelihood that a limit order will execute. Firms must assess competing markets rather than assume their existing routing arrangement remains adequate.
The practical argument for PFOF is that it can help fund cheaper access while supporting satisfactory execution. The objection is that a broker may retain revenue that could otherwise support better customer outcomes. Neither position can be resolved by pointing to a zero commission alone.
The 2020 Robinhood Settlement
On December 17, 2020, Robinhood agreed to pay a $65 million civil penalty to settle SEC charges concerning misleading disclosures and failures to satisfy its duty of best execution. The firm settled without admitting or denying the findings.
The SEC’s announcement of the Robinhood settlement stated that inferior execution prices had deprived customers of $34.1 million in aggregate, even after accounting for commission savings. The findings concerned historical conduct, including misleading communications between 2015 and late 2018.
The distinction between those figures matters. The $65 million was the civil penalty; $34.1 million represented the execution disadvantage identified in the order after commission savings.
This case demonstrated why the relevant comparison is total trading cost rather than the advertised commission. It did not establish that every PFOF arrangement harms customers, or that a broker charging commissions necessarily delivers better execution. A finding about one firm and period should not become a verdict on every business using the model.
What Order-Routing Disclosures Can Reveal
Order-routing reports make part of this business model inspectable. Rule 606 requires disclosures about brokers’ handling of customer orders in national market system stocks and listed options. Public quarterly reports provide information about routing destinations and financial arrangements. FINRA’s 2026 review of customer order handling identifies incomplete reports, omitted payments and inaccurate PFOF statements among its findings.
These reports help answer where orders go and what financial relationships may influence their routing. They do not, on their own, prove that one broker delivers better execution than another.
A broker receiving more routing revenue might handle more orders, different products or a different mix of customers. Comparing total receipts without adjusting for those differences can produce a confident answer to the wrong question.
A more useful assessment separates three issues:
- Explicit charges: What commissions, subscriptions and other fees apply to the intended activity?
- Execution outcomes: What evidence exists about prices, speed and execution likelihood for comparable orders?
- Account economics: What interest is paid on cash, and what borrowing or other service charges apply?
The weighting depends on how the account is used. A frequent trader and an investor making occasional purchases may reasonably focus on different costs.
What Commission-Free Brokerage Changed
In the broader history of stock brokers, commission-free trading marks a change in how customers evaluate the service. The visible transaction charge became less useful as a summary of the commercial relationship.
For the hypothetical small investor paying $5 to invest $100, removing that charge is a real benefit. But that benefit does not settle questions about execution, cash returns or paid extras. Equally, the existence of those questions does not make the commission saving imaginary.
The durable lesson is to distinguish price from total cost. Zero commission describes one line of a fee schedule. Payment for order flow describes one revenue arrangement. Neither is a complete judgment on a broker’s value. That judgment requires examining what the customer pays, what the broker earns and what result the customer receives.