BID TerminalOpen complete report
Research library Banks

Back of Napkin

Interactive Brokers Group, Inc. IBKR

Three-pass checkedFresh as companies report

Customer margin borrowing grew 67% in a year, to $108.5B, which is where most of that profit comes from.

IBKR · price with moving averages

Daily · 6MWeekly · 3Y
$13$36$58$80$102 Sep '23Apr '24Nov '24Jun '25Jan '26Aug '26 BID
EMAs82140

Source: market data.

The business

Interactive Brokers is a brokerage built as software rather than as a firm. Thomas Peterffy automated market making in the 1980s and then pointed the same machinery at customer execution, which is why a company with 5.2 million client accounts employs a fraction of the people its competitors do. Commissions are low because the cost of the next order is nearly zero.

The money is mostly not commissions. Customers hold $930.3B of equity in their accounts and the firm earns a spread on the cash portion, and they borrow $108.5B against those holdings on margin, which is a secured loan at a rate the customer accepts because leaving would mean moving the account. Interactive Brokers is a lender with an execution platform attached.

Inside the complete Back of Napkin

  1. 01The business
  2. 02The numbers
  3. 03Management
  4. 04How it fails or surprises you
  5. 05The shape of the payoff
  6. 06Closing thoughts
  7. 07Methodology

Continue with IBKR

Get the complete Back of Napkin free.

Choose this as your free complete report. No card required.

Read the complete report

More company research

View all research
PJT Partners Inc. PJTPJT Partners grew a record second quarter 20% with all three of its engines, strategic advisory, private capital, and restructuring, rising at once, a combination the model was explicitly designed to produce. Back of Napkin Piper Sandler Companies PIPRPiper Sandler just printed the best first half in its history, advisory revenue up 34% to a record, and the stock sits 22% below its February high anyway. Back of Napkin Houlihan Lokey, Inc. HLIWhile every other advisory bank was printing records this quarter, Houlihan Lokey's revenue fell 16%, and the stock has been cut 39% from its high for being the one name that zigged. Back of Napkin Stifel Financial Corp SFStifel just reported the best second quarter in its history, and it did so with 66% of segment revenue coming from wealth management, not the deal desk everyone watches. Back of Napkin