Interactive Brokers Posts 4.31 Million DARTs, 5.68M Accounts in October

Interactive Brokers closed October with 5.68 million client accounts, up 34% year-on-year and up 2% from September, while daily average revenue trades fell to 4.31 million, down 4% from October 2025 but up 5% month-on-month, according to the broker's monthly activity metrics.

The account number is the story's strongest signal. The DART number shows the counter-current. Clients keep arriving. Per-account activity is thinning.

What do the balance sheet figures show?

Client equity totalled $928.6 billion in October. That is up 19% year-on-year but down 4% from September, when the figure stood at $964.7 billion.

Client margin loan balances moved the other way. They rose 31% annually and 2% from September, reaching $106.8 billion. Leveraged positioning grew while asset values slipped.

Client credit balances, including insured bank deposit sweeps, stood at $180.5 billion. That marks a 15% annual gain against a 3% monthly decline. Insured bank deposit sweeps accounted for $6.2 billion of the total.

The mix tells desks two things. Cash keeps flowing into the platform at scale. But October's market drawdown dented both equity and credit balances across the book.

What are the per-account economics?

The broker reported 163 annualised average cleared DARTs per client account.

Average commission per cleared commissionable order came in at $2.46, including exchange, clearing and regulatory fees. That figure is the unit economics of the retail flow machine: modest per ticket, multiplied across more than four million daily trades.

For comparison, September's release showed 5.6 million accounts, $964.7 billion in client equity and roughly 4.1 million DARTs. September trading activity rose 6% year-on-year, while DARTs fell 4% from August. Two consecutive months of monthly DART softness followed by an October rebound of 5%.

October's figures show continued growth in client accounts and margin loans, while client equity and credit balances declined from the previous month.

How cheap is IBKR execution, measured not asserted?

Interactive Brokers also published execution quality data for IBKR PRO clients trading US-regulated stocks, and the numbers deserve a close read because they come with a stated methodology.

• The average US Regulation National Market System stock trade was valued at $23,670 in October.
• Total cost of executing and clearing these stocks ran at approximately 1.1 basis points of trade value, measured against a daily volume-weighted average price benchmark.
• The net cost for the rolling 12-month period was 2.4 basis points.

The VWAP benchmark is the key qualifier. Measured cost is not the same as achieved cost, and desks comparing brokers should note both the benchmark choice and the gap between the monthly print and the rolling annual figure.

Why does the AI trading authorization matter?

The October numbers follow Interactive Brokers' expansion of its AI trading services. The broker introduced IBKR Autonomous Trading, which lets eligible clients authorize connected AI platforms to monitor more than 75,000 stocks, options and ETFs and submit supported orders on their behalf.

Clients set trading instructions and risk limits up front. They do not approve each order individually. That delegation model moves AI from research tool to execution agent, with pre-set guardrails standing in for per-order human sign-off.

For execution desks, this changes the shape of retail order flow at the margin. Algorithmic submission under standing risk limits could compress order sizes, tighten submission windows and add a layer of machine-driven behavior on top of the 4.31 million daily tickets already crossing the platform.

The compliance question is unresolved in the announcement: what audit trail and kill-switch mechanics govern an autonomous agent acting under delegated authority. Brokers and vendors watching this launch will want those details before the model spreads.

Interactive Brokers' next monthly release will show whether October's DART rebound holds and whether account growth keeps outrunning per-account activity.