Interactive Brokers Group Inc - Ordinary Shares - Class A

Record performance + very strong profitability (good) - The firm reported record commissions, net interest, and total net revenue, plus record client metrics including total accounts, account adds, client equity, and total client DARTs. - Pre-tax margin: 77%, “seventh consecutive quarter” above 70%—a key indicator of strong operating leverage. - Commissions rose 30% YoY to a new record, driven by robust trading volumes in stocks/options/futures.

Client activity and balance growth are strong, lifting “idle cash” (good + slightly surprising) - Trading activity increased vs. last year, with clients taking on more risk via margin loans or derivatives. - New accounts up 34% drove client uninvested cash balances up 27% YoY to a record $182B. - Client equity rose 40% to $930B—showing both asset growth and increased participation. - Fully rate-sensitive customer balances: $28.4B (vs. $22.8B a year ago), supporting higher interest earnings.

Revenue/cost structure remains efficient; key driver is higher balances and rates (neutral-to-good) - Net interest income rose 23% YoY to >$1B, primarily from higher balances (margin loans and segregated cash), partially offset by interest paid on customer cash. - Gross transactional profit margin: 83% (commissions remain very “high quality” relative to execution/clearing economics). - Execution/clearing costs up 22% YoY largely due to reinitiation of SEC regulatory fees (previously zero since mid-2Q25), but management emphasizes these are largely pass-through.