A brokerage commission is a transaction charge for an agency trade. Learn how commissions are calculated, disclosed, and compared with spreads and other costs.
A commission is a transaction-based charge paid for executing or arranging a securities trade, usually when a broker-dealer acts as the customer’s agent. The term can also describe compensation that a brokerage firm pays to a representative, but the amount charged to the customer and the amount ultimately received by an individual representative are not necessarily the same.
A commission is only one part of trading cost. A trade can have no stated commission and still involve a bid-ask spread, dealer markup or markdown, options contract charge, product expense, currency-conversion cost, or other brokerage fee.
$0 commission offer applies only to the transactions and conditions stated by the broker. It does not mean the account, product, or execution is cost-free.
flowchart LR
A["Customer places a securities order"] --> B{"How does the firm act?"}
B -->|"Agent for customer"| C["Execution plus separately stated commission or service charge"]
B -->|"Principal using firm inventory"| D["Customer price may include dealer markup or markdown"]
C --> E["Review confirmation, fee schedule, and total execution cost"]
D --> E
E --> F["Add relevant spread, product, financing, currency, and account costs"]
The capacity shown for the transaction matters. Calling every form of dealer compensation a commission can hide the difference between an explicit charge and compensation incorporated into the security’s price.
Common structures include:
| Structure | Simplified calculation | What to verify |
|---|---|---|
| Flat per order | Stated amount for each eligible order | Product, channel, order type, and whether separate charges apply |
| Per share | Shares executed x rate per share | Minimum commission, partial fills, and volume tiers |
| Per contract | Contracts executed x rate per contract | Base trade charge, exercise or assignment fees, and exchange charges |
| Percentage of value | Transaction value x stated rate | Minimum, maximum, breakpoint, and valuation basis |
| Tiered schedule | Different rates at stated activity or asset levels | Measurement period and which trades qualify |
| Broker-assisted charge | Online rate plus an assistance charge, or a separate schedule | What conduct counts as broker assistance |
The applicable fee may depend on the product, market, account program, country, currency, order channel, or negotiated institutional schedule. A formula is useful only after identifying the correct schedule.
Assume a hypothetical broker charges $0.01 per share with a $10 minimum for an agency stock trade. A customer buys 750 shares.
Calculated commission = 750 x $0.01 = $7.50
Because the minimum is higher, the commission charged would be $10, not $7.50. If the same schedule applies when the customer later sells all the shares, the two explicit commissions would total $20.
That $20 is not the complete round-trip cost. The purchase may execute at the ask, the sale may execute at the bid, market prices may move, and other charges or taxes may apply. The example illustrates a commission calculation; it does not estimate an actual broker’s rates or a likely investment result.
| Feature | Agency transaction | Principal transaction |
|---|---|---|
| Firm’s role | Acts for the customer in executing the order | Buys from or sells to the customer using the firm’s own account |
| Common compensation label | Commission or service charge | Markup on a sale to the customer or markdown on a purchase from the customer |
| How cost appears | Often stated separately | Often reflected in the transaction price, subject to applicable disclosure rules |
| Core comparison | Commission plus execution quality and other costs | Customer price relative to the prevailing market and other costs |
| Main evidence | Confirmation, fee schedule, order and execution records | Confirmation, prevailing-market evidence, dealer records, and price comparison |
FINRA Rule 2121 requires fair commissions or service charges in agency transactions and fair prices in principal transactions, considering the relevant circumstances. Its supplementary material describes the often-cited 5% Policy as a guide rather than a rule. A charge below 5% is not automatically fair, and the policy is not a universal commission schedule.
| Cost | What it pays for | Usually transaction-based? | Where to look |
|---|---|---|---|
| Commission | Broker acting as agent to execute or arrange a trade | Yes | Fee schedule and trade confirmation |
| Brokerage Fee | Account, platform, transfer, wire, service, or transaction activity | Sometimes | Account agreement, fee schedule, and statement |
| Markup or markdown | Dealer compensation in a principal trade | Yes | Confirmation and transaction-price evidence |
| Bid-ask spread | Difference between quoted buying and selling prices | Arises when trading | Market quote and execution record |
| Management Fee | Investment-management services | Usually ongoing | Advisory agreement or fund disclosure |
| Expense Ratio | A fund’s annual operating expenses | Ongoing within the fund | Prospectus and shareholder report |
| Margin interest | Borrowing in a margin account | Accrues over time | Margin agreement, rate schedule, and statement |
A useful comparison adds costs that are economically relevant without labeling all of them commissions.
Zero commission generally means the broker does not impose its standard explicit commission on a covered trade. Coverage can differ by security, order method, market, account, or service. Options contracts, broker-assisted orders, foreign securities, over-the-counter transactions, transfers, subscriptions, margin borrowing, and currency conversion may follow different schedules.
The customer can also bear costs that are not separate line-item commissions:
FINRA cautions that free trading does not mean free investing. The correct comparison is the total account, product, and transaction cost for the investor’s actual use, not the headline commission alone.
Commissions directly reduce the amount retained from a transaction. They also affect incentives. A person or firm paid when a transaction occurs may have an economic reason to favor more trades, a particular product, or a particular transaction structure.
For U.S. retail customers, Regulation Best Interest applies when a broker-dealer makes a covered securities transaction or investment-strategy recommendation. The SEC’s framework includes disclosure of material fees and costs and material conflicts associated with the recommendation. It does not make every commission arrangement improper; it requires the relationship, costs, conflicts, and recommendation to be evaluated under the applicable standard.
For an investment manager using client commissions to obtain research or brokerage services, a separate Soft Dollars analysis may apply. That issue differs from the ordinary question of how much commission appears on a customer’s trade.
For a disputed charge, retain the order ticket, timestamps, execution report, confirmation, statement, fee schedule, account agreement, communications, and any correction or adjustment record.
$0 with $5 while ignoring spreads, product expenses, foreign-exchange costs, or service fees.This article provides general U.S.-focused financial and regulatory education. It is not tax, legal, accounting, brokerage, compliance, or investment advice for a particular person, account, firm, security, or transaction.