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IBKRInteractive Brokers · Insider ownership research

Interactive Brokers insiders sold $36.5M in the past 12 months. How much of their stake is that?

About 5.8% overall. As a group they still hold 92% of their starting shares. The biggest individual seller, Earl Nemser, sold shares equal to 48% of starting holdings, but more vested, so the stake grew.

Updated Oct 8, 2026 from SEC filings · covers Oct 9, 2025 to Oct 8, 2026
How this comparesMore of their stake sold than at 186 of the 311 other companies we can measure (#126 of 312)See ranking
2
buyers among officers and directors (10 trades), past 12 months
0%
of sales were under disclosed trading plans, past 12 months
2 of 11
officers and directors sold shares, past 12 months
Recent activity · past 30 days, Sep 9, 2026 to Oct 8, 2026
Oct 1, 2026Lori Conkling bought 25 shares ($2K). The total stake went from 2.6K to 2.6K shares that day.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Lori Conkling
Director
25$85.42n/a2.6KOct 1, 2026Oct 5, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Is this normal? Less than usual: less than one-twentieth of the 5-year average. 2 insiders sold; the average is 3 a year. Year by year
Latest filing: Filed Oct 5 for a purchase on Oct 1. Lori Conkling bought 25 shares ($2K). Filing
42 SEC ownership filings in the period · See the evidence

What stands out

Two insiders sold more than 25% of vested holdings: Earl Nemser (48% of holdings, $30.7M, none under a disclosed plan) and Lawrence Harris (32% of holdings, $5.8M, none under a disclosed plan).Earl Nemser: largest sale, Jan 22, 2026 · Lawrence Harris: largest sale, Apr 28, 2026
Two directors bought shares: Jill Bright (400 shares, $26K) and Lori Conkling (250 shares, $20K).Jill Bright: purchase, Oct 23, 2025 · Lori Conkling: purchase, Feb 25, 2026

Percentages cover 9 of 11 officers and directors. Left out: Thomas Frank (most holdings were last confirmed in 2020); Lori Conkling (held no vested shares at the start). Disclosed company stock is not an insider's whole wealth.

Who sold, and how much of their stake

Officers and directors, past 12 months. Each bar is the insider's vested stake at the start of the period (Oct 8, 2025). The gold part is what they sold.

SoldRest of starting stakeAdded during the period
Earl Nemser
Vice Chairman, Director
48% · $30.7MNo plan disclosed
Lawrence Harris
Director
32% · $5.8MNo plan disclosed
Amounts, filings and trading plans for each seller

Selling by month

Officers and directors, Oct 2025 to Oct 2026. Each sale is counted once: under a disclosed plan, else to cover taxes, else no plan disclosed.

Disclosed planTo cover taxesNo plan disclosed
Oct 2025: $3.8M no plan disclosedOctNovDecJan 2026: $30.7M no plan disclosed$30.7MJanFebMarApr 2026: $2.0M no plan disclosedAprMayJunJulAugSepOct

Common questions

Is the Interactive Brokers CEO selling stock?

No. Milan Galik reported no open-market sales in the past 12 months.

Why are Interactive Brokers insiders selling?

Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 0% of sales by value ran under 10b5-1 trading plans disclosed in the filings and 100% had no disclosed plan. A trading plan schedules sales in advance.

Are any Interactive Brokers insiders buying?

Yes. 2 officers or directors reported 10 purchases in the past 12 months (Form 4 code P, which includes private purchases).

How much of their stake did Interactive Brokers insiders sell?

About 5.8% overall. As a group they still hold 92% of their starting shares. The biggest individual seller, Earl Nemser, sold shares equal to 48% of starting holdings, but more vested, so the stake grew. That covers the 12 months to Oct 8, 2026 and counts vested shares reported on SEC Forms 3, 4 and 5, which is not an insider's whole wealth.

The evidence

Who sold2 officers and directors: amount, % of holdings, trading plan
Who soldAmount% of holdingsTrading plan
Earl Nemser
Vice Chairman, Director
$30.7M
400K shares
48%No plan disclosed
Lawrence Harris
Director
$5.8M
81K shares
32%No plan disclosed
The full ownership picture11 of 11 insiders fully reconciled · 11 officers and directors

Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.

InsiderHeld Oct 8, 2025SoldHeld Oct 8, 2026Still held
Milan Galik
i
Includes unvested RSUs, amount not disclosed. Starting holdings restated for a probable stock split. Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Chief Executive Officer, Director
4.14M03.22Mno sales
Vesting, gifts, unvested awards and holding lines for Milan Galik
0shares vested or exercised
0gifted (net of own trusts)
−255Kwithheld by the company for taxes
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
  • Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A Common Stock3,245,0003,215,389
Immediate Family MemberClass A common stock895,6880

Additional holdings last reported May 8, 2015, not confirmed since: 2,908,004 shares. Not included in any total or percentage on this page.

Paul Brody
i
Includes unvested RSUs, amount not disclosed.
Chief Financial Officer, Director
2.89M02.86Mno sales
Vesting, gifts, unvested awards and holding lines for Paul Brody
0shares vested or exercised
0gifted (net of own trusts)
−83Kwithheld by the company for taxes
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock2,885,4962,856,806
PJB Holdings LLCClass A common stock6,9286,928
Earl Nemser
i
Includes unvested RSUs, amount not disclosed.
Vice Chairman, Director
828K−400K1.23M+49%
Vesting, gifts, unvested awards and holding lines for Earl Nemser
0shares vested or exercised
0gifted (net of own trusts)
−22Kwithheld by the company for taxes
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A Common Stock427,812429,344
EN Holdings LLCClass A common stock400,000803,568
Thomas Frank
!
Most of this insider's holdings were last confirmed in 2020. Confirmed in the last three years: 251,518 shares. Not confirmed since: 3,261,832 shares, left out of this row. "Still held" is not shown because it would cover only the smaller, confirmed part.
Executive Vice President
269K0252Ksee note
Vesting, gifts, unvested awards and holding lines for Thomas Frank
0shares vested or exercised
0gifted (net of own trusts)
−32Kwithheld by the company for taxes
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
  • Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock269,304251,518

Additional holdings last reported May 8, 2020, not confirmed since: 3,261,832 shares. Not included in any total or percentage on this page.

Lawrence Harris
i
Starting holdings restated for a probable stock split. Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Director
254K−81K173K68%
Vesting, gifts, unvested awards and holding lines for Lawrence Harris
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Starting holdings restated for a probable stock split.
  • Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Held throughShare classOct 8, 2025Oct 8, 2026
DirectClass A Common Stock253,704173,482

Additional holdings last reported Jul 30, 2007, not confirmed since: 20,000 shares. Not included in any total or percentage on this page.

Denis Mendonca
i
Includes unvested RSUs, amount not disclosed. Starting holdings restated for a probable stock split.
Chief Accounting Officer
145K0145Kno sales
Vesting, gifts, unvested awards and holding lines for Denis Mendonca
0shares vested or exercised
0gifted (net of own trusts)
−11Kwithheld by the company for taxes
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock145,072145,071
Jill Bright
i
Starting holdings restated for a probable stock split.
Director
9.9K011Kno sales
Vesting, gifts, unvested awards and holding lines for Jill Bright
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Starting holdings restated for a probable stock split.
Held throughShare classOct 8, 2025Oct 8, 2026
DirectClass A common stock9,90411,082
William Peterffy
i
Includes unvested RSUs, amount not disclosed. Starting holdings restated for a probable stock split.
Director
9.3K010Kno sales
Vesting, gifts, unvested awards and holding lines for William Peterffy
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock9,34810,126
Nicole Yuen
i
Includes unvested RSUs, amount not disclosed. Starting holdings restated for a probable stock split.
Director
9.3K010Kno sales
Vesting, gifts, unvested awards and holding lines for Nicole Yuen
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock9,34810,126
Richard Repetto
i
Includes unvested RSUs, amount not disclosed. Starting holdings restated for a probable stock split.
Director
2.3K03Kno sales
Vesting, gifts, unvested awards and holding lines for Richard Repetto
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Starting holdings restated for a probable stock split.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock2,2683,046
Lori Conkling
i
Includes unvested RSUs, amount not disclosed.
Director
002.6Kno sales
Vesting, gifts, unvested awards and holding lines for Lori Conkling
0shares vested or exercised
0gifted (net of own trusts)
none reportedunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
Held throughShare classOct 8, 2025Oct 8, 2026
Direct
includes unvested RSUs, amount not disclosed
Class A common stock02,584

11 of 11 insiders fully reconciled: starting holdings plus reported transactions match ending holdings (11 exactly, 0 with a minor or footnoted difference). Percentages cover 9 of 11 officers and directors. Left out: Thomas Frank (most holdings were last confirmed in 2020); Lori Conkling (held no vested shares at the start). "Still held" compares ending with starting vested shares; a plus sign means the holding grew.

What explains the selling$36.5M of sales by plan status, purpose, seller and month

Officer and director open-market sales: $36.5M across 481,000 shares. Plan status and stated purpose are separate questions, and a sale can have both.

By plan status

No plan disclosed · $36.5M

Sales with no 10b5-1 plan and no tax reference in the filing. $30.7M of it is Earl Nemser. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: Earl Nemser, Jan 22, 2026

Taxes

403,332 shares ($34.0M) were withheld by the company for taxes, which isn't a market sale.

Purchases · 2 buyers (10 trades)

2 officers and directors bought shares in this period, in 10 trades(Form 4 code P). Across all their filings on record there are 38 purchase trades.

SellerShares soldProceedsUnder a disclosed planShare of totalSales dates
Earl Nemser
Vice Chairman, Director
400K$30.7M0%84%Jan 22, 2026 to Jan 27, 2026
Lawrence Harris
Director
81K$5.8M0%16%Oct 23, 2025 to Apr 28, 2026

Sales by month

MonthSale proceedsDisclosed planTo cover taxesNo plan disclosed
Oct 2025$3.8M$0$0$3.8M
Nov 2025$0$0$0$0
Dec 2025$0$0$0$0
Jan 2026$30.7M$0$0$30.7M
Feb 2026$0$0$0$0
Mar 2026$0$0$0$0
Apr 2026$2.0M$0$0$2.0M
May 2026$0$0$0$0
Jun 2026$0$0$0$0
Jul 2026$0$0$0$0
Aug 2026$0$0$0$0
Sep 2026$0$0$0$0
Oct 2026$0$0$0$0
Is this normal? Selling year by year5 earlier years to compare with

Less than usual: less than one-twentieth of the 5-year average. 2 insiders sold; the average is 3 a year.

12 months endingShares soldInsiders who soldProceeds
Oct 8, 2026
Latest 12 months
481K2$36.5M
Oct 8, 2025
1 year earlier
1.35M2$86.6M
Oct 8, 2024
2 years earlier
4.29M3$97.0M
Oct 9, 2023
3 years earlier
7.96M4$162M
Oct 9, 2022
4 years earlier
20.67M3$354M
Oct 9, 2021
5 years earlier
29.29M3$481M

Open-market sales (Form 4 code S) by people who were officers or directors, in split-adjusted shares. Earlier years include people who have since left. A sale that an outside holder also reports (a family trust, a fund) is counted with outside holders in every year. Shares, not dollars, are compared, so a change in the stock price doesn't look like a change in selling. Years the filings don't fully cover are shown but left out of the average.

Known gaps and uncertaintyEvery officer and director reconciles

Every officer and director reconciles for this period.

Inferred typo: the share class "Class A Comon Stock" is treated as the same class as "Class A Common Stock" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (Earl Nemser, 346,692 shares): old title, new title

Inferred typo: the share class "Class A Comon Stock" is treated as the same class as "Class A common stock" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (Paul Brody, 2,015,276 shares): old title, new title

External context: we only cite outside events when a documented connection exists. None is shown for this period.

Sources and methodology1,504 filings from SEC EDGAR, and how we read them

All 1,504 Forms 3, 4 and 5 filed for Interactive Brokers (SEC CIK 1381197) from May 3, 2007 to Oct 5, 2026, retrieved from SEC EDGAR on Oct 8, 2026. Prices are the ones reported in each filing, often weighted averages.

Probable 4-for-1 stock split on or before Jun 17, 2025 (split date stated in a footnote). Splits aren't reported as transactions; 12 holding lines changed by exactly this ratio, so earlier share counts are restated.

Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.

Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".

Full methodology

Former or inactive filers (12)No filing in 18 months; last reported balances, not in any total
NameLast filedLast reported balance
Thomas PeterffyFeb 24, 20256,064,728 shares, last reported balance as of Feb 20, 2025
Philip UhdeJan 9, 202410,098,372 shares, last reported balance as of Dec 31, 2023
Gary KatzJan 6, 20237,712 shares, last reported balance as of Dec 31, 2022
John DamgardJan 6, 20228,752 shares, last reported balance as of Dec 31, 2021
Wayne WagnerJan 5, 201510,292 shares, last reported balance as of Dec 31, 2014
Richard GatesJan 22, 201361,932 shares, last reported balance as of Jan 18, 2013
Vi TcvDec 21, 201210,160 shares, last reported balance as of Dec 20, 2012
Vi TcvDec 21, 201218,800,000 shares, last reported balance as of Dec 20, 2012
Hans StollFeb 16, 201016,772 shares, last reported balance as of Dec 31, 2008
Ivers RileyFeb 16, 201016,772 shares, last reported balance as of Dec 31, 2008
Philip DeFeoAug 2, 200720,000 shares, last reported balance as of Jul 31, 2007
Kenneth WinstonNo balance on record