Interactive Brokers ended August with $962.8 billion in client equity, putting the electronic broker within touching distance of the $1 trillion level as its customer base grew to a record 5.46 million accounts.
The Nasdaq-listed broker reported 4.276 million Daily Average Revenue Trades, or DARTs, during August, up 23% from a year earlier but 3% below July’s 4.426 million. The monthly decline in trading activity contrasted with another strong increase in assets and customer numbers.
Client equity climbed 35% from $713.2 billion in August 2025 and 6% from $906.7 billion in July. That represents an increase of roughly $56.1 billion in a single month and nearly $250 billion over the past year.
Client accounts reached 5.46 million, up 35% year over year and 3% from July’s 5.317 million. In absolute terms, Interactive Brokers added about 143,000 accounts during August and roughly 1.4 million over the past 12 months.
The growth was also visible in client borrowing.
Ending margin loan balances reached $101.5 billion, 41% higher than a year earlier and 1% above July’s $100.7 billion. The broker had $71.8 billion in margin loans at the end of August 2025.
Client credit balances, meanwhile, increased to $185.6 billion, including $6.4 billion held through insured bank deposit sweeps. That was 27% higher than a year earlier and 3% above July.
The simultaneous rise in client equity, cash balances and margin borrowing gives Interactive Brokers considerably more financial activity to monetize even when trading volumes fluctuate from month to month.
That dynamic was already visible in the company’s second-quarter results.
Interactive Brokers reported commission revenue of $673 million for the three months through June, up 30% year over year, while net interest income increased 23% to $1.06 billion. The broker attributed the increase in interest income mainly to higher average customer margin loans and credit balances, even as lower benchmark interest rates reduced yields.
Average customer margin loans during the second quarter were $96.6 billion, compared with $60.9 billion a year earlier, while average client credit balances increased to $171.7 billion from $130 billion.
August’s ending figures show those balances have continued to grow since the quarter closed.
Trading Activity Eases From July
The softer part of the August report came from trading frequency.
DARTs declined 3% sequentially to 4.276 million, while annualized cleared DARTs per client account dropped to 168. That compares with 180 in July and 187 in August 2025.
That means the broker is serving far more customers and processing more trades overall than a year ago, but the average account is trading somewhat less frequently.
Average commission per cleared commissionable order was $2.52 in August, down from $2.56 in July and $2.68 a year earlier.
Stock orders averaged 626 shares and generated an average commission of $1.99. Equity-options orders averaged 6.2 contracts and $3.60 in commission, while futures orders averaged three contracts and generated $4.17.
Interactive Brokers also reported an improvement in its disclosed execution-cost measure.
For IBKR Pro customers trading U.S. Reg-NMS stocks, the all-in cost of execution and clearing was about 2.1 basis points of trade value against the company’s daily VWAP benchmark in August, down from 4 basis points in July. The rolling 12-month figure stood at 2.5 basis points.
The average U.S. Reg-NMS stock trade was worth $22,288 during the month.
The client growth comes while Interactive Brokers continues widening its geographical and product reach. During August, it added Brazilian futures through B3, opened access to the Bucharest Stock Exchange and introduced a new Latin American account-funding route through Paysafe’s SafetyPay. The broker provides access to more than 170 markets globally.
Analysis: The $1 Trillion Number Matters More Than the DART Dip
The obvious headline number is $962.8 billion.
Interactive Brokers is now less than $40 billion away from having $1 trillion in client equity on its platform. Given that equity increased by $56 billion just between July and August, that threshold no longer looks distant, although monthly market movements mean there is no guarantee it will be crossed immediately.
More important than the round number is how Interactive Brokers got there.
Client equity stood at $713.2 billion only one year ago. The additional $249.6 billion cannot be interpreted entirely as new customer deposits because rising asset prices also increase the value of portfolios already held at the broker.
But account growth provides evidence that this is not simply a market-appreciation story.
Interactive Brokers has added around 1.4 million accounts in 12 months. Its customer base increased at roughly the same 35% rate as client equity. That suggests expansion of the platform itself remains an important part of the asset growth.
The margin figure is arguably even more interesting.
Client margin loans have risen from $71.8 billion to $101.5 billion in a year — growth of about 41%. Margin lending is important because it feeds directly into interest income. The second-quarter results already showed Interactive Brokers generating more than $1 billion in quarterly net interest income despite lower rates.
A larger loan book can partially offset pressure from falling yields.
There is still one number worth watching carefully: DARTs per account.
Total DARTs increased 23% year over year, but accounts grew 35%. Annualized cleared DARTs per account consequently fell from 187 to 168.
That does not necessarily indicate weakening demand. New customers often trade less than Interactive Brokers’ traditional professional and highly active users, so broadening into a larger retail audience could naturally lower average trading frequency.
But it creates an important distinction for future results.
Interactive Brokers can continue growing revenue by adding accounts and attracting assets even without every customer trading more frequently. Cash balances generate interest economics, margin loans generate interest income, and active customers continue producing commissions.
That gives the company several revenue engines rather than making earnings entirely dependent on trading volume.
The August numbers therefore tell two stories at once. Trading activity cooled modestly from July, and activity per account is lower than a year ago. Yet the financial base underneath that activity is expanding much faster: more customers, more equity, more cash and more borrowing.
For Interactive Brokers, crossing $1 trillion in client equity would make for a clean milestone. The more consequential number may already have arrived: margin loans above $100 billion show that the rapidly expanding customer base is not merely opening accounts but increasingly putting capital to work.