Payment for order flow is a behind-the-scenes arrangement in which your brokerage gets paid by a wholesale market-making firm for sending your stock or options orders to that firm instead of to a public exchange like the NYSE or Nasdaq. The payments are small per trade, but across millions of orders they add up to billions of dollars a year and are the main reason most U.S. brokerages can offer commission-free trading. For a typical small retail investor, the arrangement usually produces a fill at a slightly better price than the public quote. Whether that benefit holds up on larger orders, in options, or in volatile markets is a harder question, and it’s the reason this practice keeps returning to the regulatory agenda.
How a Routed Order Actually Moves
When you tap “buy” in a brokerage app, the order does not travel directly to a public exchange. The brokerage’s routing software decides where to send it, and in most cases the destination is a wholesale market maker rather than an exchange. The handoff happens in milliseconds.
The wholesaler then fills your trade from its own inventory or matches it against another incoming order inside its private system, bypassing the public order book. After the trade executes, the wholesaler sends a small payment back to the brokerage. For equities, those payments average roughly 20 cents per 100 shares. A 500-share order might generate about a dollar for your broker. The money settles between firms periodically, and nothing is deducted from your account.
The money moves from wholesaler to broker; your order data moves the other way. Your broker earns revenue without charging you commission, and the wholesaler earns the tiny spread between buy and sell prices on a very large number of trades.
Who Gets Paid and Who Pays
Three parties make the system work. You place the trade. Your brokerage decides where it goes. A wholesale market maker on the other end executes it and pays your broker.
Wholesaling is heavily concentrated. Citadel Securities alone handles roughly 35% of all U.S. listed retail equity volume, and Virtu Financial is the other dominant firm. Between them, they execute the bulk of retail stock trades in the country. Brokerages pick among them based on a mix of payment rates and execution quality.
On the broker side, firms like Robinhood lean heavily on this revenue. In 2025, Robinhood reported $2.6 billion in transaction-based revenues out of $4.5 billion in total revenue, making order-flow-related income the majority of its earnings.1Robinhood Markets, Inc. Q4 2025 Robinhood Exhibit 99.1 Larger, more diversified brokerages receive PFOF too, but it accounts for a smaller share of their business.
One venue type you probably won’t encounter: dark pools. They also execute off-exchange, but they’re built for large institutional orders and generally don’t pay brokerages for retail flow.2FINRA. Can You Swim in a Dark Pool?
What It Means for the Price You Get
Execution quality for a retail trade is measured against the National Best Bid and Offer, the best publicly quoted price across all exchanges at the moment your order arrives.3U.S. Securities and Exchange Commission. Measuring Real Execution Quality: Benefits to Retail Are Significantly Understated Wholesalers frequently offer price improvement, meaning they fill at a price slightly better than the NBBO. If the best public buy price is $10.05, a wholesaler might fill you at $10.048. Over many trades, those fractions of a cent accumulate.
Wholesalers can afford to pay for and improve on retail orders because that flow is predictable. A typical retail buyer is not trading on information that will move the stock seconds later, unlike many institutional or algorithmic traders. That predictability makes retail orders cheap to internalize, and wholesalers compete for them by offering fast fills and tight pricing on standard-sized orders in liquid stocks.
The picture shifts in thinly traded stocks and in sharp market swings. Spreads widen, response times stretch, and the price improvement you’d normally see can shrink or disappear. In those moments, the fill depends on the wholesaler’s internal algorithm rather than on open competition among many participants on a public exchange.
Research from the University of California, Irvine, placing more than 85,000 simultaneous identical market orders across multiple brokerages, found transaction costs ranged from roughly 0.07% to 0.45% depending on which broker handled the order. The study concluded the existence of PFOF alone did not drive the differences; the bigger factor was how each broker’s chosen venues actually executed the trades. Which broker you use matters more than whether PFOF is in the chain.
For a typical retail investor buying a few hundred shares of a large-cap stock, the price improvement from a wholesaler likely exceeds what an old-style $5 to $10 commission would have cost. The math is less clear on larger orders, in less liquid stocks, and in options, where spreads are wider. Most small retail traders come out ahead under the current system, but the opacity makes it very hard to verify that on any single trade.
Options Trades Carry Higher Stakes
Options generate far more PFOF revenue than stocks. About two-thirds of all PFOF payments come from options routing, and the per-share rate runs roughly double: around 40 cents per 100 shares versus 20 cents for equities. A $1,000 investment in a $5 option contract generates roughly ten times the PFOF revenue of the same dollar amount in a $25 stock.4Oxford Academic. Payment for Order Flow and Option Internalization
The structure differs too. On options exchanges, wholesalers often hold Designated Market Maker seats with a “five-lot allocation privilege,” which lets them fill the first five contracts of any order they route to the exchange as long as they’re quoting at the national best price. The privilege applies regardless of their place in the queue, effectively letting them step ahead of competitors. DMM seats are concentrated: the top two firms hold nearly 60% of all seats, and the seats rarely change hands.4Oxford Academic. Payment for Order Flow and Option Internalization
Price Improvement Mechanism auctions add another twist. The initiating market maker proposes a price, competitors can submit better ones, and the initiator keeps a unique ability to match the best competing bid. The combination of DMM privileges and auction mechanics gives the options PFOF market higher barriers to entry and less competitive pressure than the equity side. If you trade options actively, this is where the hidden costs of PFOF are most likely to matter to you.
The Best Execution Rule Behind the Scenes
Brokerages can’t legally send your order to whoever pays the most. FINRA Rule 5310 requires every broker-dealer to “use reasonable diligence to ascertain the best market” for your trade and to execute it at a price “as favorable as possible under prevailing market conditions.”5FINRA. 5310. Best Execution and Interpositioning Relevant factors include the stock’s liquidity, the size of the order, and the number of venues the broker examined.
Firms that route to wholesalers or internalize order flow must perform a “regular and rigorous” review of execution quality at least quarterly, comparing the quality their current arrangements deliver against what competing venues could offer. FINRA requires firms to specifically consider the existence of PFOF arrangements as a factor in that comparison.5FINRA. 5310. Best Execution and Interpositioning If a review shows materially better execution available elsewhere, the broker must adjust its routing or document why it isn’t.6FINRA. Best Execution
The conflict is obvious. A broker receiving millions in PFOF has a financial interest in continuing to route to the paying wholesaler, but a legal duty to send orders wherever execution is best. FINRA examinations have flagged firms for failing to adequately address PFOF-related conflicts in their routing decisions.6FINRA. Best Execution The SEC has made broker-dealer order routing and best execution a priority area for its examinations in fiscal year 2026.7U.S. Securities and Exchange Commission. FY 2026 Examination Priorities
How to See What Your Broker Is Doing
Two SEC rules give you a window into your broker’s PFOF practices, though neither is written for easy reading.
Rule 606 Quarterly Routing Reports
Every broker-dealer must publish a quarterly report listing the top venues where customer orders were sent, broken down by order type (market, limit, and so on) and split into equity and options categories. For each venue, the report has to disclose the total dollar amount and per-share amount of any PFOF received, plus a discussion of the material aspects of the broker’s relationship with the venue, including volume-based payment tiers and minimum flow agreements.8eCFR. 17 CFR 242.606 – Disclosure of Order Routing Information9U.S. Securities and Exchange Commission. Responses to Frequently Asked Questions Concerning Rule 606 of Regulation NMS
The reports must stay on a free, publicly accessible website for three years.8eCFR. 17 CFR 242.606 – Disclosure of Order Routing Information You can find them through FINRA’s data portal, which aggregates reports from participating broker-dealers and includes a glossary for interpretation.10FINRA. About NMS Equity and Options Routing Reports (SEC 606(a) Reports) Most brokerages also post their reports somewhere in a regulatory disclosures section of their website.
Rule 607 Account-Level Disclosure
Rule 607 requires your broker to tell you in writing, when you open an account and annually after that, about its PFOF policies. The notice must describe the nature of the compensation received and explain how the broker decides where to route orders when PFOF is involved, including whether orders can be executed at prices better than the NBBO.11eCFR. 17 CFR 242.607 – Customer Account Statements In practice, this arrives inside the paperwork flood of opening an account, and most people never read it.
What’s Changing in 2025 and 2026
Two regulatory changes will reshape how execution quality is measured and reported.
Smaller Tick Sizes
Starting in November 2025, the SEC’s amended Rule 612 introduced a half-penny tick size ($0.005) for stocks whose time-weighted average quoted spread is $0.015 or less. Stocks with wider spreads keep the one-cent minimum.12U.S. Securities and Exchange Commission. Tick Sizes – A Small Entity Compliance Guide Public exchanges can now quote tighter prices for heavily traded stocks, which may narrow the gap between exchange prices and the prices wholesalers offer. Whether this reduces PFOF by making exchanges more competitive, or simply tightens the already-small margins, is still playing out.
Expanded Rule 605 Reporting
The bigger change is the overhauled Rule 605, adopted by the SEC in March 2024 with a compliance date now extended to August 1, 2026.13Federal Register. Extension of Compliance Date for Disclosure of Order Execution Information The amendments extend execution-quality reporting beyond market centers to include larger broker-dealers. They also capture fractional share orders, odd-lot orders, and larger-sized orders that older reporting missed, and require execution timing measured in milliseconds or finer.14U.S. Securities and Exchange Commission. Disclosure of Order Execution Information Once in effect, the reports should let retail investors compare execution quality across brokerages and wholesalers using standardized data for the first time.
The Rule That Didn’t Happen
In 2022 the SEC proposed an Order Competition Rule that would have required certain retail orders to be exposed to competitive auctions before a wholesaler could fill them. The SEC formally withdrew the proposal on June 12, 2025, stating it did not intend to finalize the rule.15U.S. Securities and Exchange Commission. Order Competition Rule For now, the existing PFOF model stays intact, and the SEC is relying on improved transparency through Rule 605 and continued examination work.
Elsewhere, the practice is being shut down. Under MiFIR Article 39a, the EU prohibits investment firms acting for retail or professional clients from receiving any fee, commission, or non-monetary benefit from a third party for routing orders to a particular venue. Member states where PFOF existed before March 2024 could apply for a temporary exemption, but those expire on June 30, 2026.16European Securities and Markets Authority. Article 39a Prohibition of Receiving Payment for Order Flow The UK and Canada had already prohibited it. The U.S. remains the largest market where PFOF is permitted, and the withdrawal of the Order Competition Rule suggests a federal ban is not imminent.
The Structural Catch
Debate over PFOF usually focuses on individual fills, but the practice has effects on the market that go beyond any one trade. When wholesalers pull retail orders off public exchanges, those orders become hidden liquidity, executed privately and not contributing to public price discovery until after the fact. An SEC study found that siphoning uninformed retail trades off exchanges leaves public venues with a higher concentration of information-driven institutional orders, which raises adverse selection risk for the market makers that remain there. The study linked this to wider bid-ask spreads and greater volatility on the public exchanges that actually set prices.17U.S. Securities and Exchange Commission. How Does Payment for Order Flow Influence Markets? Evidence from Robinhood Crypto Token Introductions
That creates a circular problem for retail investors. You may get a slightly better price than the NBBO on your individual trade, but the diversion of retail orders from public markets may be widening the NBBO itself. If the public quote would be tighter with more retail participation on exchanges, the “price improvement” you receive is being measured against a benchmark that PFOF has helped loosen. That circularity is why regulators keep returning to the topic even after stepping back from an outright ban, and why the expanded Rule 605 data arriving in 2026 is worth paying attention to when it lands.