What Is Payment for Order Flow?

Payment for Order Flow (PFOF) is a practice in financial markets where a brokerage firm receives compensation from a third party — typically a market maker — for directing client orders to them for execution. Instead of sending a client’s trade directly to an exchange like the New York Stock Exchange (NYSE) or Nasdaq, the broker routes it to a market maker or other liquidity provider who then executes the trade, often outside of a public exchange.

This practice is common in retail investing and is one way some brokerages can offer commission-free trading. The revenue from PFOF can help offset operational costs that would otherwise be passed on to investors. However, the practice has been the subject of regulatory scrutiny and debate, particularly around whether it serves investors’ best interests.

How the Process Works

When an investor places a trade — for example, to buy 100 shares of a stock — the brokerage firm has several routing options. It could send the order to a stock exchange or to a market maker who offers to pay the broker for routing that order to them. Market makers profit from the spread between the bid and ask prices and are willing to share a portion of that profit with brokerages as payment for the order flow.

Market makers typically handle large volumes of trades and may be able to execute orders faster or at better prices than public exchanges, especially in highly liquid securities. In theory, if the investor receives "price improvement" — meaning their trade is executed at a better price than was publicly quoted — the practice may benefit the end user. However, this outcome depends on how the market maker prioritizes execution quality.

Why Brokerages Use It

PFOF is a significant revenue source for many retail brokerage firms, particularly those that offer zero-commission trading. Without charging a commission per trade, these brokerages must find alternative revenue streams. Payment for order flow helps make that model financially viable.

For example, Robinhood Markets Inc. — one of the most well-known commission-free platforms — has historically derived a large percentage of its revenue from PFOF. The company routes trades to several market makers and receives payments in return, which are disclosed in quarterly filings.

Brokerages argue that PFOF enables them to keep trading costs low for users while maintaining access to liquidity and competitive pricing. However, the practice introduces a potential conflict of interest: brokers may have an incentive to route orders based on compensation received rather than the quality of execution for the client.

Regulatory Oversight and Criticism

The Securities and Exchange Commission (SEC) permits PFOF but requires that brokers adhere to their duty of “best execution.” This means they must consider several factors — including price, speed, and likelihood of execution — and not simply route trades based on payment alone.

Critics of PFOF argue that it distorts the incentives brokers have when routing trades. Instead of seeking the best price or execution quality, brokers might prioritize relationships with the market makers that pay the most. This may disadvantage retail investors, especially in volatile or low-volume trading scenarios where execution quality becomes more important.

The GameStop trading frenzy in early 2021 brought renewed attention to PFOF practices. Lawmakers and regulators questioned whether retail investors were receiving fair treatment and whether the PFOF model contributed to instability or conflicts of interest. In response, the SEC began exploring changes to market structure that could include curbing or banning PFOF, increasing transparency, or requiring more robust best execution standards.

Some jurisdictions have taken firmer stances. For instance, PFOF is banned in the United Kingdom and Canada, based on the belief that it undermines market transparency and investor outcomes.

Impact on Investors

From the investor’s perspective, PFOF may not be immediately visible. Most retail investors see the ability to trade stocks without paying commissions as a clear benefit. However, the true cost may be embedded in the execution price — if the order is filled at a slightly worse price than what might have been achieved on an exchange, the investor loses out in a less obvious way.

This is why regulators require brokers to provide regular disclosures, such as Rule 606 reports, which detail order routing practices and the extent of PFOF arrangements. Still, many investors do not read or understand these disclosures, making it difficult to assess whether they are receiving competitive execution.

Over time, even small differences in execution prices can add up, particularly for active traders. For long-term investors, the effect may be less pronounced, but the concern remains: are brokerages acting in the best interests of their clients?

The Bottom Line

Payment for Order Flow is a practice that supports the zero-commission trading model but raises important questions about transparency, execution quality, and broker incentives. While legal in the United States and regulated by the SEC, it has faced increasing scrutiny and debate, especially as retail participation in markets has surged.

Whether PFOF benefits or harms investors depends on how brokers manage their obligations and how well market makers fulfill their role. Investors who want to better understand the tradeoffs involved may wish to review their broker’s order routing disclosures and stay informed about ongoing regulatory developments.