[IBKR] Interactive Brokers: Q3 2026 Earnings Test Net Interest Income After Margin Dip

Interactive Brokers is an automated global broker whose customers trade stocks, options, futures, currencies, bonds and funds on more than 170 exchanges and market centers in 40 countries from a single account[1], and it is scheduled to report results for the third quarter of 2026, ending September 30, 2026, with an earnings call on 2026-10-20[2]. In the latest disclosed quarter, the second quarter of 2026, net revenue rose 28% to $1.896 billion, with net interest income up 23% to $1.057 billion, commissions up 30% to $673 million and diluted EPS of $0.69 versus $0.51 a year earlier[3]; at quarter end the company had 5.19 million accounts, $930.3 billion of customer equity and $108.5 billion of margin loans, up 34%, 40% and 67% year over year[4]. The company gives no revenue or profit guidance and discloses only rate sensitivity in its 10-Q: based on June 30 balances, a 25 basis point rise in U.S. dollar benchmark rates would add about $81 million of annualized net interest income, and an equal rise in all other relevant benchmark rates would add about $38 million more[5]. Analyst estimates compiled by Drillr put mean third-quarter net revenue at $1.898 billion (4 analysts, range $1.857 billion to $1.950 billion) and mean diluted EPS at $0.688 (6 analysts, range $0.667 to $0.698), essentially flat with the second quarter's $1.896 billion and $0.69[6]; the Drillr earnings calendar shows $0.689 EPS and $1.995 billion of revenue, but that table's revenue basis does not match the income statement, so revenue comparisons should rely on the estimates table[2].

Three things matter most in the Interactive Brokers Q3 2026 earnings report. The first is whether net interest income can hold its second-quarter record of $1.057 billion: margin loans fell to about $100.7 billion in July[7], 7% below the June-end level, and second-quarter securities lending included special-security income from hot IPOs, so weakness in either balances or lending would show up directly in a line that made up 55.7% of net revenue[8]. The second is whether commissions keep pace with account growth: accounts kept growing about 3% a month in July and August, but annualized trades per cleared account fell from 207 in the second quarter to 168 in August[9], and the gap between the decline in third-quarter commissions and the decline in trade counts will show how far account growth offsets weaker activity. The third is whether the 77% pretax margin holds as revenue cools: second-quarter non-interest expenses rose 17% to $440 million and customer bad debt reached $10 million[10], against only $1 million in the first quarter[11], so a drop in commissions alongside rising fixed costs would give the margin its first test from the revenue side.

Company Background and Business Structure

Interactive Brokers is a founder-controlled global broker that uses technology in place of staff. Thomas Peterffy, the current chairman, founded the firm in 1977 and began its electronic brokerage business in 1993; it is headquartered in Greenwich, Connecticut, and Milan Galik is chief executive. In its 10-K the company calls itself "an automated global broker," and customers can trade global products in 29 currencies, with cryptocurrencies executed and held by third-party providers[1].

The listed company, IBG, Inc., is a holding shell, so public shareholders share in only about a quarter of operating profit. IBG, Inc.'s main asset is roughly 26.5% of the membership interests of the operating entity IBG LLC, while the remaining 73.5% or so is held by IBG Holdings LLC, owned by Peterffy and his affiliates, management and employees[12]. As a result, of $1.456 billion in consolidated second-quarter pretax income, only $312 million ended up as net income available to common stockholders[13].

The company reports a single brokerage segment, but its revenue breaks cleanly into four parts. Of $1.896 billion in second-quarter net revenue, net interest income was $1.057 billion, commissions $673 million, other fees and services $87 million and other income $79 million[8]; net interest income comes from margin loans secured by securities, from investing segregated customer cash in short-term Treasuries and reverse repos, and from securities lending. Customers can choose fixed pricing, tiered pricing or IBKR Lite, which charges no commission on U.S. stocks and ETFs, and the payments market makers make for Lite orders are also booked as commissions[14]; other income is mainly currency and investment gains and losses from holding the firm's equity in GLOBAL, a basket of 10 currencies, and the company's adjusted figures remove both items[4][15].

The customer base is highly diversified, and no single client can swing revenue. The company divides customers into cleared customers, who use its execution and clearing services and make up the large majority, and non-cleared customers, who use execution only; they include individuals, traders, hedge funds, registered investment advisers, proprietary trading firms and introducing brokers that white-label the whole platform for their own clients, and no single customer accounted for more than 2% of commissions in 2025[16]. At the end of the second quarter the company had 5.185 million accounts, $930.3 billion of customer equity, $182.4 billion of customer cash and $108.5 billion of margin loans[4].

Financial History and Current Position

Over the past two years, Interactive Brokers has grown both its scale and its margins. Net revenue rose from $5.185 billion in 2024 to $6.205 billion in 2025, pretax income rose 29% from $3.695 billion to $4.771 billion and diluted EPS rose from $1.73 to $2.22, adjusted for the four-for-one split in June 2025[17], while the pretax margin climbed from 71% to 77%[18]. Commissions drove the 2025 gain, rising 27% to $2.149 billion, while net interest income rose only 13% to $3.563 billion[17], because the average federal funds effective rate fell from 5.14% to 4.21% and net interest margin narrowed from 2.35% to 2.08%, leaving balance growth to offset lower rates[19].

Growth in the first half of 2026 ran faster than in 2025. First-quarter net revenue was $1.669 billion[11] at a 77% pretax margin[20]; second-quarter net revenue rose 28% to $1.896 billion, with commissions up 30%, net interest income up 23%, non-interest expenses up 17% to $440 million and pretax income of $1.456 billion[8], net income available to common stockholders of $312 million[13] and diluted EPS of $0.69[3].

Second-quarter net interest income grew entirely on balances, not on rates. Average margin loans rose 59% to $96.596 billion and average customer cash rose 32% to $171.674 billion, but net interest margin fell from 2.07% to 1.93% and the margin loan yield fell from 4.67% to 4.10%[21]. On the balance sheet, total assets were $247.3 billion at the end of June, 99.0% of them liquid, consolidated equity was $22.3 billion, aggregate excess regulatory capital across operating subsidiaries was $14.2 billion and the company had no long-term debt[22]; management put excess capital after required buffers at about $10.3 billion, up about $1.1 billion from the prior quarter[23].

First-half operating cash flow was large, but it reflects customer money moving in and out rather than cash the company generated for itself. Operating cash flow of $9.827 billion came mainly from a $22.4 billion increase in customer cash and a $20.7 billion increase in securities loaned, partly offset by increases of $18.5 billion in customer receivables such as margin loans and $13.1 billion in segregated securities[24]. The cash that actually reaches owners comes through distributions and dividends: in 2025 IBG LLC distributed $1.224 billion to its members, of which IBG, Inc. received $319 million[25]; in the first half of 2026 it distributed $512 million to IBG Holdings and paid $75 million in common dividends, after raising the quarterly dividend in April from $0.08 to $0.0875 per share[20].

Operating Model

Net interest income depends on balances, yields and the rate paid on customer cash, and balance changes reach the income statement in the same quarter. Second-quarter net revenue equaled $1.057 billion of net interest income plus $673 million of commissions, $87 million of other fees and services and $79 million of other income[8]; within net interest income, $96.596 billion of margin loans at a 4.10% yield produced $988 million, $97.647 billion of segregated cash and securities at 3.32% produced $809 million and the company paid $956 million of interest on $171.674 billion of customer cash, a 2.23% rate[21], while securities lending including interest on cash collateral produced $343 million, up from $251 million a year earlier[26]. The spread on customer cash comes from the 0.50 percentage point the company keeps on U.S. dollar cash and from not paying interest on small accounts and balances under $10,000[19]; higher benchmark rates lift both loan yields and yields on segregated assets, and by the company's sensitivity estimate each 25 basis point rise in U.S. dollar rates adds about $81 million of annualized net interest income[5].

Commissions equal trade count times commission per order, and trade count equals accounts times how often each account trades. In the second quarter, daily average revenue trades (DARTs) were 4.824 million, cleared accounts traded 207 times a year on an annualized basis and commission per order was $2.64[9], slightly below $2.65 a year earlier because of smaller foreign exchange orders and greater capture of liquidity rebates[14]. Trading frequency is highly sensitive to volatility and major market events and shows up in the same quarter: customer average daily volumes in stocks, options and futures rose 14%, 17% and 2% in the second quarter, while the average VIX fell from 23.7 to 18.3[27].

The cost base is mostly fixed, so almost every change in revenue falls through to pretax income. Of $440 million in second-quarter non-interest expenses, execution, clearing and distribution fees were $142 million, including $34 million of SEC Section 31 transaction fees that resumed in April[10], compensation and benefits were $182 million for an average of 3,249 employees, up 6%[28], general and administrative expenses were $68 million and customer bad debt was $10 million[29]. Execution costs move with volume and are partly passed through to customers, while pay and administrative costs are largely fixed, which is how the second-quarter pretax margin reached 77%, the seventh straight quarter above 70%[23].

Pretax income passes through two layers of ownership and tax before it becomes EPS, and the company keeps most of its own cash as regulatory capital. In the second quarter the operating subsidiaries paid $64 million of local income tax, the remaining profit was allocated to IBG, Inc. at its 26.4% average ownership, and IBG, Inc. then paid $54 million of U.S. income tax, leaving $312 million for common stockholders[13]; when IBG Holdings exchanges membership interests for listed shares, IBG, Inc.'s ownership and share count rise together, so the net effect on EPS is limited. Capital spending is small, with $44 million spent on fixed and intangible assets in the first half[24], the company does not buy back stock, and management said it has been pitched more acquisition targets but found none worth pursuing[23].

Industry and Competitive Position

Interactive Brokers competes on low prices, global access and automation, and its main price weapon sits on both sides of the interest line. The 10-K lists competitors including large prime brokers building electronic platforms, direct-market-access and online brokers, zero-commission brokers, trading software vendors and traditional brokers, and acknowledges that some rivals have more resources and can charge lower or zero commissions[30]. The company pays interest on U.S. dollar cash at the benchmark rate minus 0.50 percentage point and says its rates are among the highest in the industry[19]; it prices margin loans at a spread over benchmark rates and says those rates are among the lowest[31].

Rapid account growth shows that this pricing attracts customers, with Asia and introducing brokers as important sources. In 2025 accounts rose 32% to 4.399 million and DARTs rose 40% to 3.685 million[32]; the company's monthly figures show 5.46 million accounts at the end of August 2026, up 35% year over year. On the second-quarter call, management described the introducing broker pipeline as very strong, with more new partners being established firms expanding their offerings, and said it has seen more account and asset transfers from Tiger Brokers and Futu after mainland China tightened rules on unlicensed cross-border brokerage[23].

New products are expanding, but their financial contribution cannot yet be verified. In July the company launched IBKR Prediction Markets, which combines contracts from ForecastEx, CME and Kalshi, opened access to the Korea Exchange, and received preliminary conditional approval from the Office of the Comptroller of the Currency for a national trust bank charter, with the bank expected to operate by the end of 2026[23]; access to Brazil's B3 is also under way. None of these businesses reports revenue separately, so they do not change the main drivers of the third quarter, and because citable peer financials are limited, the evidence for the company's cost and pricing advantages rests mainly on its own disclosures.

Core Debates

After margin loans pulled back in July, can net interest income hold its second-quarter record?

Net interest income is the company's largest revenue source, and its growth now rests entirely on balance expansion. It made up 55.7% of second-quarter net revenue, far more than commissions; the average U.S. dollar rate was about 0.70 percentage point lower than a year earlier and net interest margin fell from 2.07% to 1.93%, yet net interest income still rose 23%[21]. The key in the third quarter is therefore not rates but whether margin loans and customer cash keep growing, and whether extra securities lending income from hot IPOs in the second quarter disappears; if net interest income falls back below $1 billion, the assumption that account growth turns automatically into interest income would need to be discounted.

The second-quarter baseline is clear, but part of it may not repeat. The company attributed second-quarter net interest income of $1.057 billion to higher average margin loans and customer cash, partly offset by lower benchmark rates; net interest income on customer balances rose $233 million, driven by increases of $41.7 billion, $35.7 billion and $19.0 billion in average customer cash, margin loans and segregated cash and securities[33]. Average margin loans were $96.6 billion, average customer cash was $171.7 billion and all-in securities lending net interest was $343 million[26]; management said plainly that the timing and size of special-security income from hot IPOs such as SpaceX are unpredictable[23].

The July and August monthly data support two opposite readings, and the transmission path determines which will show up first in the income statement. The optimistic reading is that margin loans of $101.5 billion and customer cash of $185.6 billion at the end of August were both above second-quarter averages, and that the Federal Reserve's rate hike on September 16 turned rates from a headwind into a slight tailwind. The cautious reading is that margin loans dropped from $108.5 billion at the end of June to $100.7 billion at the end of July, a 7% fall in one month, which suggests part of the quarter-end peak came from June's trading surge, while SpaceX specials tied to its June listing may not recur in the third quarter. The chain runs from account growth and rising stock prices to higher customer cash and margin loan balances, which are priced off benchmark rates into interest income and expense; short demand and hot IPOs lift lending balances and borrow fees; and benchmark rates move loan yields, yields on segregated assets and the rate paid on customer cash, which is set at the benchmark minus 0.50%.

The October 8-K will separate these readings with quarterly average balances, lending income and net interest margin. Watch whether third-quarter net interest income is at least the second quarter's $1.057 billion and whether it reaches $1.080 billion; whether average margin loans exceed $100 billion and average customer cash tops $178 billion; whether all-in securities lending holds $300 million and whether the company's description of special-security income changes; and the updated rate sensitivity in the 10-Q along with management's comments on fourth-quarter spreads after the hike. If special-security lending income falls back to the year-earlier level and consumes the interest gained from balance growth, or a market pullback repeats July's 7% one-month drop, the current view that balance growth can offset narrower spreads would weaken.

Accounts are growing about 3% a month while each account trades less. Will commissions fall back from their record?

Commissions are the second-largest revenue line and nearly all incremental commission revenue becomes pretax income, so whether account growth turns into commissions matters a great deal. Second-quarter commissions were $673 million, 35.5% of net revenue[8]; the market's core story about Interactive Brokers is fast account growth, but commissions depend on accounts multiplied by trades per account. Accounts kept growing about 3% a month in July and August, yet annualized trades per account fell from 207 in the second quarter to 168, and total trades ran nearly 10% below the second quarter; if third-quarter commissions fall with trade counts, account growth is not yet enough to offset lower activity, and if they fall clearly less, the quality of that growth is confirmed.

The second quarter combined peak activity with a peak account count. Commissions rose 30%, DARTs rose 36% to 4.824 million, annualized trades per account held at 207, flat with a year earlier, and commission per order was $2.64[9]; management explained the flat per-account figure by a strong market lifting activity in both new and existing accounts, and by the mix between large active hedge funds and smaller introducing broker accounts balancing out over time[23]. Monthly data for July and August show accounts rising from 5.317 million to 5.46 million, but DARTs falling from June's high to 4.426 million and 4.276 million, annualized trades per account dropping to 180 and 168, and commission per order at $2.56 and $2.52.

It is not yet possible to tell whether the drop in activity is cyclical or structural. One reading holds that the second quarter was an activity peak driven by the SpaceX listing, a rally in Korean chip stocks and June's trading high, so the third quarter is simply a return to normal and account growth will keep lifting commissions over a longer period; the other holds that more new accounts come from small introducing broker clients who trade less, so account growth will systematically overstate commission growth. The chain runs from volatility and major events to trades per account and from direct, adviser and introducing broker sign-ups to account count, which together produce DARTs; order size, product mix and liquidity rebates set commission per order; and DARTs times commission per order yields commissions, which reach pretax income after execution costs that move partly with volume.

The gap between third-quarter declines in commissions and DARTs, along with September trades per account, can partly separate these readings. Watch whether third-quarter commissions are at least $620 million and fall less than DARTs; whether September DARTs and annualized trades per account stop falling and return above 180; whether quarter-end accounts reach 5.6 million and what management says about the sources of new accounts; and whether commission per order stays above $2.50. If third-quarter commissions fall in step with DARTs, the second quarter's activity was a peak lifted by major events; if new accounts are mostly small, low-activity accounts, account growth will overstate commission growth for a long time.

If revenue cools, can Interactive Brokers keep its 77% pretax margin?

A highly automated cost base is what separates Interactive Brokers from traditional brokers, and it is the source of the 77% pretax margin. The company serves $930.3 billion of customer equity with about 3,250 employees[28]; second-quarter expenses rose 17%, faster than in the first quarter, but mostly because of SEC fees passed through to customers and a one-time customer bad debt charge[10]. If commissions fall in the third quarter while fixed costs keep rising, the margin will face its first test from the revenue side: holding above 75% would show the cost structure truly flexes, while a drop below 74% would show the high margin depends on revenue peaks like the second quarter's.

The second-quarter cost structure shows that most costs do not shrink with revenue. Of $440 million in non-interest expenses, execution, clearing and distribution fees were $142 million, including $34 million of SEC Section 31 fees, and expenses equaled 23% of net revenue versus 25% a year earlier[10]; customer bad debt of $10 million came mainly from customer losses tied to a corporate action during the quarter[29]. The adjusted pretax margin was 77%, the same as in the first quarter[15].

Whether the margin holds depends on whether flexible costs can offset rising fixed costs. The optimistic reading is that execution costs will fall with volume, regulatory fees are pass-through items, pay is only about 10% of net revenue and net interest income is still growing, so the margin can hold without another commission record. The cautious reading is that fixed costs are rising, with headcount up 6% and compensation up 12%[28], advertising and legal reserves also higher, and customer bad debt up from $1 million in the first quarter to $10 million as margin lending grows; if third-quarter commissions fall to about $600 million while net interest income stays flat, the margin would be squeezed toward 75%. The chain runs from trading volume to execution and clearing costs net of liquidity rebates, from headcount and share price to largely fixed pay, and from sharp market drops and concentrated positions to customer bad debt; net revenue minus non-interest expenses gives pretax income, of which IBG, Inc. takes about 26.4%.

Third-quarter results will give the first reading of the margin as revenue falls. Watch whether the adjusted pretax margin is at least 76%; whether non-interest expenses stay within $460 million and execution and clearing fees fall with volume; and whether customer bad debt returns below $10 million and whether the 10-Q describes any new concentrated-position or sharp-drop losses. If fixed costs keep rising while revenue falls and push the margin below 74%, or customer bad debt jumps as margin balances grow, the high margin depends more on revenue peaks than the cost structure suggests.

Risks and Falsifiers

Tail credit risk on margin loans is the most direct balance sheet risk. At the end of June the company had extended $108.9 billion of margin loans, and the 10-Q notes that in fast markets or with concentrated collateral, collateral may not cover customer losses, a risk it expects to grow with the business[34]; management said it monitors this continuously and is comfortable with current risk levels[23]. Customer bad debt runs straight through non-interest expenses, the second quarter's $10 million was already 10 times the first quarter's, and a single extreme market move could cause losses far beyond the usual quarterly range while also shrinking margin balances and net interest income; if third-quarter customer bad debt is no more than $10 million and the 10-Q describes no new large customer default or concentrated-position loss, the risk has not materialized.

The ownership and exchange structure decides how much profit public shareholders receive. Publicly held IBG, Inc. owns only about 26.5% of IBG LLC, with the rest held by Peterffy-controlled IBG Holdings, which can exchange membership interests for listed shares, and on July 31 the company registered another 2,499,567 shares, worth $224 million, for such an exchange[12]. Only $312 million of second-quarter pretax income of $1.456 billion reached common stockholders, exchanges raise both ownership and share count so their EPS effect depends on size, and public shareholders have limited long-term influence over governance; if IBG, Inc.'s ownership rises slightly each quarter (26.4% on average in the second quarter) and EPS growth keeps pace with pretax income growth, the structure has not eroded public holders' interests[13].

Regulatory and cross-border risk centers on Asian customers and price competition. Mainland China has tightened rules on unlicensed cross-border brokerage for mainland residents; the company says it has long complied, does not advertise on the mainland and verifies that clients do not reside there, and it has seen account and asset transfers from Tiger Brokers and Futu[23]; it also faces price competition from zero-commission brokers and large prime brokers[30]. If a regulatory shift reaches the Hong Kong subsidiary or Asian customers, part of account growth and customer assets would be affected, and Interactive Brokers Hong Kong, with $2.182 billion of net capital at the end of the second quarter, is the largest regulated subsidiary outside the U.S.[22]; if accounts keep growing about 3% a month in the third quarter and neither the 10-Q nor the call reports new regulatory limits on Asian business, the risk has not materialized.

A drop in special-security lending income and margin balances is the most direct downside for net interest income. Second-quarter lending income included specials from hot IPOs such as SpaceX, whose timing and size management calls unpredictable[23], and margin loans are highly sensitive to market pullbacks, having fallen 7% from the end of June to the end of July. If all-in securities lending net interest returned from $343 million to the year-earlier $251 million, quarterly net interest income would be about $90 million lower[26]; each $1 billion less in average margin loans costs about $10 million of quarterly interest at a 4.10% yield[21]. If third-quarter all-in securities lending is at least $300 million and average margin loans are at least $100 billion, the risk has not materialized.

A fall in trading activity from the second-quarter peak would directly lower commissions and pretax income. In July and August annualized trades per account dropped to 180 and 168, average DARTs ran 9.8% below the second quarter and commission per order was 3% to 5% lower; a mechanical calculation from those two months' DARTs and commission per order puts third-quarter commissions at about $580 million to $610 million, $60 million to $90 million below the second quarter's $673 million[8], and most of that would hit pretax income after execution costs fall with volume. If third-quarter commissions are at least $620 million and September annualized trades per account return above 180, the risk is falsified[9].

A mismatch between rigid costs and falling revenue is the most likely source of margin pressure. Second-quarter compensation rose 12% and headcount 6%[28], while third-quarter commissions may fall with volume; on the second-quarter structure, each $100 million less in net revenue, after about $10 million of execution costs that fall with volume, cuts pretax income by about $90 million and the margin by about 1 percentage point[10]. If the third-quarter adjusted pretax margin is at least 76% and non-interest expenses are no more than $460 million, the risk is falsified[15].

What to Watch Next

• Net interest income: the second-quarter baseline is $1.057 billion. At least $1.057 billion in the October 8-K confirms the current view; below $1 billion weakens it.
• Average margin loans and customer cash: the second-quarter baselines are $96.6 billion and $171.7 billion. Margin loans of at least $100 billion and customer cash above $178 billion confirm the view.
• All-in securities lending net interest: the second-quarter baseline is $343 million versus $251 million a year earlier. Holding $300 million confirms the view; a return to the year-earlier level weakens it.
• Commissions against DARTs: the second-quarter baselines are $673 million and 4.824 million DARTs. Commissions of at least $620 million falling less than DARTs confirm the view; a decline in step weakens it.
• Trades per account and account count: the baselines are 207 annualized trades in the second quarter and 5.185 million accounts at the end of June. A return above 180 in September and accounts near 5.6 million confirm the view.
• Commission per order: the second-quarter baseline is $2.64. Holding above $2.50 confirms the view.
• Adjusted pretax margin: the second-quarter baseline is 77%. At least 76% confirms the view; below 74% weakens it.
• Non-interest expenses and customer bad debt: the second-quarter baselines are $440 million and $10 million. Expenses no higher than $460 million and bad debt no higher than $10 million confirm the view; a jump in bad debt weakens it.

Conclusion

Interactive Brokers' results rest on two forces: customer balances drive net interest income, 55.7% of net revenue, and trading activity drives commissions, 35.5%, while a highly automated cost base turns most changes in both lines straight into pretax income. The company posted a record second quarter with $1.896 billion of net revenue and a 77% pretax margin, backed by $22.3 billion of consolidated equity, $14.2 billion of excess regulatory capital and no long-term debt[22]. The central unresolved relationship is whether account growth, from 5.185 million at the end of June to 5.46 million at the end of August, can keep turning into net interest income and commissions of the same size now that margin loans slipped in July and trades per account are falling.

Only one independent commentary published after the second-quarter results can be verified word for word, so it represents one commentator's view rather than a shared market judgment. In an August 20 article, Brett Schafer of The Motley Fool cited July margin loans topping $100 billion, up 49% year over year, as a sign that the bull market's "animal spirits" were in full swing and that Interactive Brokers was taking share in trading; he argued that net interest income growth should accelerate from the second quarter's 23% as long as balances kept growing quickly in August and September, named falling rates as the main headwind to net interest income, and said the share price reflected investors neither worrying about rate cuts nor doubting that accounts would keep growing at the pace of recent years[7]. That view sits on the optimistic side of the first debate, inferring faster net interest income growth from year-over-year margin loan growth; it does not address the 7% drop in July balances from the end of June or the possibility that second-quarter special-security lending income falls back, and after the Federal Reserve's September hike, the rate headwind he flagged has instead become a slight tailwind for the fourth quarter. No verifiable independent commentary yet addresses the other two debates, on whether commissions can keep up with account growth and whether the margin can hold as revenue cools.

The current view would be materially strengthened by a combination of observations: third-quarter net interest income of at least $1.057 billion, with average margin loans above $100 billion and all-in securities lending holding $300 million; commissions of at least $620 million falling less than DARTs; and an adjusted pretax margin of at least 76% with customer bad debt no higher than $10 million. Conversely, net interest income back below $1 billion, commissions sliding with DARTs to around $600 million, a margin below 74% or a jump in customer bad debt would indicate that the second-quarter records came more from a one-time trading surge and special-security income than from lasting capacity built by account growth.

Sources

[1] IBKR 10-K filed 2026-02-27 · business overview · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[2] Drillr earnings calendar (updated 2026-09-23) · IBKR 2026-10-20 call and 3Q26 estimates · 2026-09-23 · Drillr earnings calendar · https://gateway.drillr.ai/mcp/private

[3] IBKR 8-K filed 2026-07-21 · 2Q26 financial highlights · 2026-07-21 · 8-K · https://www.businesswire.com/news/home/20260721157186/en/Interactive-Brokers-Group-Announces-2Q2026-Results/

[4] IBKR 8-K filed 2026-07-21 · 2Q26 business highlights and dividend · 2026-07-21 · 8-K · https://www.businesswire.com/news/home/20260721157186/en/Interactive-Brokers-Group-Announces-2Q2026-Results/

[5] IBKR 10-Q filed 2026-08-06 · interest rate sensitivity · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[6] Drillr analyst_financial_estimates (updated 2026-09-23) · IBKR 3Q26 consensus · 2026-09-23 · Drillr analyst_financial_estimates · https://gateway.drillr.ai/mcp/private

[7] The Motley Fool 2026-08-20 · Interactive Brokers' Margin Loans Grew 49% in a Year to $100.7 Billion · 2026-08-20 · The Motley Fool · https://www.fool.com/investing/2026/08/20/interactive-brokers-margin-loans-grew-49-in-a-year/

[8] IBKR 8-K filed 2026-07-21 · 2Q26 income statement · 2026-07-21 · 8-K · https://www.businesswire.com/news/home/20260721157186/en/Interactive-Brokers-Group-Announces-2Q2026-Results/

[9] IBKR 10-Q filed 2026-08-06 · 2Q26 customer statistics · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[10] IBKR 10-Q filed 2026-08-06 · 2Q26 non-interest expenses and execution fees · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[11] IBKR 8-K filed 2026-04-21 · 1Q26 income statement · 2026-04-21 · 8-K · https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001381197&type=8-K&dateb=&owner=include&count=40

[12] IBKR 10-Q filed 2026-08-06 · ownership structure and Holdings exchanges · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[13] IBKR 10-Q filed 2026-08-06 · 2Q26 IBG, Inc. ownership and tax table · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[14] IBKR 10-Q filed 2026-08-06 · 2Q26 commissions · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[15] IBKR 10-Q filed 2026-08-06 · 2Q26 non-GAAP reconciliation · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[16] IBKR 10-K filed 2026-02-27 · customers · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[17] IBKR 10-K filed 2026-02-27 · FY2025 financial overview · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[18] IBKR 10-K filed 2026-02-27 · FY2025 operating results and noncontrolling interest · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[19] IBKR 10-K filed 2026-02-27 · FY2025 interest rate environment and NIM · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[20] IBKR 8-K filed 2026-04-21 · 1Q26 highlights and dividend increase · 2026-04-21 · 8-K · https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001381197&type=8-K&dateb=&owner=include&count=40

[21] IBKR 8-K filed 2026-07-21 · 2Q26 net interest income table · 2026-07-21 · 8-K · https://www.businesswire.com/news/home/20260721157186/en/Interactive-Brokers-Group-Announces-2Q2026-Results/

[22] IBKR 10-Q filed 2026-08-06 · liquidity, equity and regulatory capital · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[23] IBKR 2Q26 earnings call 2026-07-21 · Drillr structured summary · 2026-07-21 · earnings-call · https://gateway.drillr.ai/mcp/private

[24] IBKR 10-Q filed 2026-08-06 · 1H26 operating and financing cash flows · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[25] IBKR 10-K filed 2026-02-27 · member distributions and stockholder dividends · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[26] IBKR 10-Q filed 2026-08-06 · 2Q26 securities lending · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[27] IBKR 10-Q filed 2026-08-06 · 2Q26 business environment: volumes and volatility · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[28] IBKR 10-Q filed 2026-08-06 · 2Q26 compensation and headcount · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[29] IBKR 10-Q filed 2026-08-06 · 2Q26 customer bad debt and income tax · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[30] IBKR 10-K filed 2026-02-27 · competition risk factor · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[31] IBKR 10-Q filed 2026-08-06 · 2Q26 business environment: rates and NIM · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[32] IBKR 10-K filed 2026-02-27 · FY2025 customer statistics · 2026-02-27 · 10-K · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000062/

[33] IBKR 10-Q filed 2026-08-06 · 2Q26 net interest income drivers · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/

[34] IBKR 10-Q filed 2026-08-06 · margin loan credit risk · 2026-08-06 · 10-Q · https://www.sec.gov/Archives/edgar/data/1381197/000138119726000147/