IBKR Q3: commission growth includes fees passed through to customers

Commission growth needs a cost comparison

Interactive Brokers reported higher third-quarter commission revenue, but the headline increase is not a clean measure of additional earnings from trading. Its October 15 release says the increase reflected both more daily average revenue trades and higher regulatory fees passed through to customers. The same release identifies higher regulatory fees as the main driver of rising execution, clearing and distribution costs.

The useful question is therefore how much revenue remained after the associated costs, rather than whether the commission line grew. That distinction matters when evaluating operating leverage: a fee collected and remitted can enlarge both sides of the income statement without creating an equivalent increase in profit. IBKR's business did grow, but the reported commission percentage alone does not establish the economics of that growth.

Put the two reported lines beside each other

For the three months ended September 30, 2026, commissions were $602 million, compared with $537 million a year earlier. Execution, clearing and distribution fees increased to $134 million from $92 million. These are quarterly figures from the consolidated income statement, not the nine-month totals shown alongside them.

Subtracting the second line from the first gives $468 million this quarter and $445 million a year earlier, an increase of $23 million, or about 5.2%. Commission revenue itself increased by $65 million, or about 12.1%. The smaller increase in the two-line difference shows why matching revenue with a related expense category changes the interpretation.

This calculation is an analytical comparison, not a company-defined profit measure. Execution, clearing and distribution fees cover more than one activity, and the subtraction excludes compensation, technology-related costs and other operating expenses. It cannot establish an exact commission-business margin. Nor does it prove that all changes in the two lines arose from the same trades.

The fee change explains part of the difference

IBKR attributed $30 million of the increase in execution, clearing and distribution fees to higher regulatory fees associated with the SEC Section 31 transaction fee rate. The entire expense category rose by $42 million. The disclosed regulatory-fee increase therefore accounts for roughly 71% of that increase; the remainder is $12 million.

The regulatory documents provide context rather than a separate estimate of IBKR's earnings. The SEC's February 27 advisory set a rate of $20.60 per million dollars of covered sales from April 4, 2026, following a zero rate through April 3. FINRA's March 17 notice confirmed the effective date and explained that FINRA obtains Section 31 fees from member firms.

Those notices concern specified transactions and the regulatory collection mechanism. They do not show the amount paid by each IBKR customer or the full composition of IBKR's commission line. In particular, the disclosed $30 million expense increase should not simply be subtracted from commission revenue and labeled an official fee-adjusted result without a matching revenue reconciliation.

More trades do not mean more revenue per order

The operating table provides another reason to avoid equating activity with pricing power. Total customer daily average revenue trades rose 18% year over year. However, commission per cleared commissionable order was $2.59, compared with $2.70 a year earlier, a decline the company rounded to 4%.

These measures have different scopes. Total customer activity and a cleared-customer per-order measure are not interchangeable denominators. Multiplying the two does not reconstruct consolidated commission revenue, and the release does not support assigning the per-order change entirely to price cuts. Product mix and the characteristics of customer orders require further investigation.

Read the evidence together: activity expanded, the per-order measure declined, and regulatory fees affected both revenue and expenses. That combination supports a more qualified assessment than a simple claim that higher trading automatically produced stronger unit economics.

What would strengthen the earnings case

The next reporting period should be assessed with the same paired revenue-and-cost comparison. A wider difference between commissions and related execution costs, accompanied by stable or improving per-order economics, would support a stronger interpretation of the trading business. Growth driven mainly by fees collected for onward payment would provide less evidence of operating improvement.

Keep that test separate from the rest of the company. Net interest income was $1.154 billion in the quarter versus $967 million a year earlier, according to the income statement. That is a distinct earnings source, not part of commission revenue. Assessing IBKR as a whole requires examining both businesses and the remaining costs.

The practical conclusion is narrow: IBKR's commission growth is real, but its quality is better judged after identifying pass-through fees, checking the associated expense line and respecting the scope of each activity measure. Future filings can clarify the mix; the current disclosure does not justify a precise, unsupported estimate of underlying commission profit.