IBKR's $182B Idle Cash and Record Commissions Face IPO Drain Risk

What happened

Interactive Brokers reported $182.4 billion in uninvested client cash for June, up 27% year-over-year, while second-quarter commission revenue hit a record $673 million, up 30%. The company's earnings remain heavily dependent on net interest income, which accounted for 61% of 2024 revenues, so idle cash balances are a critical earnings driver. The article raises the concern that Anthropic's anticipated IPO could lead clients to deploy idle cash into new issues, mechanically reducing the base on which IBKR earns interest. Our latest deep-value review rates IBKR a WAIT at $75.97 with implied base value of $75, reflecting a stretched ~21x trailing P/E and cyclically elevated trading metrics. While filings emphasize balance growth and product innovation, investors should treat IPO-driven cash outflows as a real but likely manageable risk given the stickiness of brokerage cash and offsetting commission tailwinds.

Implication

Over the next six to twelve months, investors should track whether high-profile IPOs, including Anthropic, cause a sustained decline in client idle cash and net interest income. The base case already assumes moderate NII growth, so a faster drawdown would pressure earnings toward the bear case of $65. Conversely, if cash balances remain resilient and commission growth offsets any NII softness, the stock could hold near current levels but offers limited upside given valuation. The master report's WAIT rating and $75 base value remain appropriate absent stronger evidence that trading and rate tailwinds will persist. Position sizing should stay disciplined, with accumulation considered only on a pullback toward the mid-$60s or after confirming durable margin and account growth.

Thesis delta

No material change to our WAIT thesis. The new data confirm robust commission growth and a large interest-earning cash base, but introduce a speculative near-term risk that IPO activity could divert client cash. We maintain our view that valuation leaves little margin of safety, and would only upgrade on a pullback or evidence of durable activity.