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What Is a Zero-Commission Broker?
“Zero commission” removes the visible per-trade ticket fee, but it does not remove trading costs—it shifts monetization into order routing, spreads, cash balances, financing, and securities lending, which can change execution outcomes and trader trust. For brokerage leaders, the real question isn’t “Can we advertise $0?” but “How do we earn—and what incentives does that create?”
This content is for information purposes only and does not constitute financial advice.
Zero commission is a pricing label, not “free”
Zero commission means the explicit commission line item is $0, but traders still pay through spreads, slippage, financing, and other embedded costs. In practice, “commission-free” is a different revenue architecture that can reshape execution quality and total cost. A trade can be “$0” and still be more expensive once you account for indirect costs.
Small execution differences can dominate the saved ticket fee—for example, a $0.01 worse fill on a 1,000-share order can outweigh a few dollars of commission savings.
What brokers should internalize:
- Explicit costs: the commission you charge per trade.
- Implicit costs: bid–ask spread, price improvement, and slippage.
- Balance sheet costs: margin interest and cash yield capture.
Measure what matters: Total Cost of Execution (TCE)
The most reliable way to compare “free” versus paid pricing is to measure Total Cost of Execution (TCE), not the commission line. TCE is the combined effect of execution price vs. best available price, plus spreads, slippage, and any financing and account-level costs that accrue around the trade. The research repeatedly frames “zero commission” as a headline that can diverge from all-in outcomes.
A practical, broker-friendly way to structure TCE:
- Execution: effective spread + slippage (what the trader actually paid vs. midpoint/benchmark).
- Trade fees: commissions (even if $0) and per-contract/per-lot fees where applicable.
- Financing: margin interest, overnight charges, swap/roll costs where relevant.
- Cash effect: what the broker pays on idle cash vs. what it earns (more on this below).
Broker takeaway: if your business model depends on “$0,” your TCE story must be defensible—because sophisticated traders and regulators evaluate outcomes, not marketing.
How zero-commission brokers actually earn
Zero-commission brokers replace ticket fees with revenue streams tied to routing economics, pricing control, client cash, leverage, and asset lending. These can be grouped into a few dominant buckets—each with different incentive risks and different disclosure expectations.
At a high level, the monetization map includes:
- Payment for Order Flow (PFOF) in some markets for equities/options
- Spread markup and internalization (often called “dealing” or “principal” execution)
- Cash sweep yield capture
- Margin interest and financing
- Securities lending
- Ancillary fees (withdrawals, inactivity, FX conversion, data)
Payment for Order Flow (PFOF) and routing economics (equities/options)
PFOF means a broker routes client orders to specific market makers in exchange for a fee or rebate, creating a potential conflict with best execution. The research explains the mechanism clearly: the broker “sells” order flow, and the market maker profits by capturing spread/value in execution—then shares some of that economics with the broker.
Why this matters operationally:
- Routing incentives can drift toward the highest rebate instead of the best price/fastest fill.
- Regulators have taken action when execution outcomes and disclosure controls did not match best-execution obligations (the research cites a notable enforcement case tied to PFOF incentives).
- PFOF is treated differently across jurisdictions; several major regulators view it as a structural conflict.
Broker design implication: if you use PFOF, you need strong Regulatory reporting and routing governance so your economics don’t undermine client outcomes.
Spread-only pricing and internalization
In spread-only models, the “commission” is embedded as a markup in the bid–ask spread, often when the broker (or its liquidity arrangement) acts as principal to the trade. A broker can quote a wider spread than the underlying market and retain the difference as revenue, while also controlling pricing rules in client terms.
Key operational realities:
- Internalization (often described as a “principal” model) gives the broker wide control over pricing and execution logic.
- This structure can create conflicts when the broker benefits from client losses or from wider spreads during volatility.
- “Last look” practices can cause asymmetric slippage (fills when price moves against the trader, rejections when it moves in the trader’s favor).
For brokers, this is less about “good vs bad” and more about defensibility: you need clear execution policies, monitoring, and controls aligned to Trade surveillance and best-execution obligations.
Balance sheet monetization: cash sweeps and margin financing
A major profit center for commission-free models is the spread between what a broker earns on client cash and what it pays clients, plus interest earned on margin lending. The research describes “cash sweep arbitrage” where uninvested cash is swept to partner banks, the broker earns a higher rate, pays clients a lower rate, and retains the spread.
What this means in practice:
- In higher-rate environments, cash yield capture becomes a primary subsidy for “$0 trading.”
- The research also highlights that margin economics are often central: a difference in effective APR on leverage can outweigh saved commissions over time.
Broker design implication: cash and margin are pricing products, not back-office details—your disclosure, tiering, and eligibility rules directly affect retention and trust.
Securities lending and “fully paid” programs
Brokers can earn by lending customer securities to borrowers for a fee, sometimes sharing revenue through “fully paid” lending programs—yet terms and risks are often poorly understood by traders. The research explains the mechanism and flags key considerations like voting rights loss and “cash-in-lieu” dividend tax treatment when shares are lent.
What brokers should make explicit:
- Whether lending is opt-in or opt-out
- How revenue share is calculated
- What protections change when securities are loaned
- How clients can exit the program
How “zero” can impact traders
Zero-commission monetization can show up for traders as higher effective spreads, reduced price improvement, slippage/requotes, and lower yield on idle cash—so the cost appears in outcomes, not invoices. The research repeatedly emphasizes that traders should evaluate execution quality and all-in costs, not just the absence of a ticket fee.
Trader-visible impacts brokers should expect to be questioned on:
- Effective spread: what clients actually paid vs. the midpoint at execution time.
- Price improvement: whether executions beat the displayed quote or best available benchmark.
- Fill quality: partial fills, delays, or systematically worse outcomes in fast markets.
- Requotes/rejections: particularly where “last look” or discretionary execution clauses exist.
- Idle cash drag: low sweep yields can function like an “invisible fee” for less-active clients.
Red flags traders look for in terms and execution policies
Traders interpret certain disclosures as signals that “free” may be expensive—especially broker discretion over prices/spreads, rejection rights, and PFOF language. The research includes checklists and examples of clauses that imply discretionary pricing, volatility-driven spread widening, or broad execution rejection rights.
Common “red flag” themes:
- “We set prices/spreads at our discretion” language (pricing control without guardrails).
- High-volatility rejection behavior (research cites elevated rejection dynamics during stress events).
- “Last look” or re-quote rights leading to asymmetric slippage.
Concentrated routing (e.g., most orders routed to a single wholesaler), implying weak competitive tension for price.
What brokers should do to offer “zero” responsibly
Brokers can offer low or zero explicit commissions while protecting trust by tightening execution governance, strengthening disclosures, and aligning the revenue model with best-execution obligations. Verification should be possible through standardized reports and clear execution policies—and that regulators scrutinize conflicts tied to routing and inducements.
A practical operating checklist for broker leaders:
- Document routing logic and conflicts (especially if PFOF or internalization is involved) and ensure controls are auditable.
- Publish and maintain disclosures appropriate to jurisdiction, including routing and PFOF policy disclosures where applicable.
- Monitor execution quality continuously using measurable metrics (fill rates, effective spreads, price improvement, rejection rates).
- Make cash and margin economics explicit (rates, tiers, effective APR, eligibility), because these often drive the true cost for active clients.
- Design securities lending with clarity (opt-in/opt-out, revenue share, risks, exit path).
This is also where infrastructure matters: consistent policy enforcement, clean data, and unified controls across CRM, client portal, and execution stack support stronger [Risk management] and lower operational drift.
Zero commission is a strategic pricing choice that must be backed by transparent revenue design, strong execution controls, and clear disclosures to sustain trader trust. “Free” often means monetization shifts into routing, spreads, cash, and lending—and the trader experiences the cost through execution quality and account economics, not an invoice.
FAQ
If a broker charges $0 commission, how do they make money?
They typically earn from PFOF (where allowed), spread markups/internalization, cash sweep yield capture, margin interest, securities lending, and ancillary fees—so revenue shifts from visible ticket fees to embedded economics.
Does PFOF mean I get worse prices?
Not always, but it can introduce a conflict where routing is influenced by rebates instead of best price—so traders should check routing and execution quality disclosures and compare effective spreads over time.
What is spread-only pricing, and is it really cheaper?
Spread-only means the broker embeds its fee inside the bid–ask spread; depending on markup and slippage, the all-in cost can be higher than a low-spread plus commission model—especially during volatile conditions.
What should I look for in a broker’s terms and conditions?
Look for discretion clauses (“we set prices/spreads”), rejection/requote rights, securities lending defaults, and low cash sweep yields—because these often explain how “$0” is monetized and where execution risk can concentrate.
