As of September 12, 2026, Interactive Brokers's top three insider holders are Thomas Peterffy (Chairman, 6.77Mn shares), Thomas Peterffy (Chairman, 6.77Mn shares), Thomas Peterffy (Chairman, 6.06Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Thomas Peterffy | Chairman | 12,836,332 | 0 | 12,836,332 | 63.1% | 24 Feb, 2025 |
| 2 | Milan Galik | Chief Executive Officer | 3,215,389 | 0 | 3,215,389 | 15.8% | 28 May, 2026 |
| 3 | Paul Jonathan Brody | Chief Financial Officer | 2,856,806 | 0 | 2,856,806 | 14.0% | 28 May, 2026 |
| 4 | Earl H Nemser | Vice Chairman | 0 | 803,568 | 803,568 | 3.9% | 04 Aug, 2026 |
| 5 | Thomas Aj Frank | Executive Vice President | 251,518 | 0 | 251,518 | 1.2% | 28 May, 2026 |
| 6 | Lawrence E Harris | Director | 173,482 | 0 | 173,482 | 0.9% | 29 Apr, 2026 |
| 7 | Denis Mendonca | Chief Accounting Officer | 145,071 | 0 | 145,071 | 0.7% | 28 May, 2026 |
| 8 | Jill Bright | Director | 11,082 | 0 | 11,082 | 0.1% | 26 Jan, 2026 |
| 9 | Philip Uhde | Director | 10,288 | 0 | 10,288 | 0.1% | 09 Jan, 2024 |
| 10 | William Peterffy | Director | 10,126 | 0 | 10,126 | 0.0% | 26 Jan, 2026 |
| 11 | Nicole Yuen | Director | 10,126 | 0 | 10,126 | 0.0% | 26 Jan, 2026 |
| 12 | John M. Damgard | Director | 8,752 | 0 | 8,752 | 0.0% | 06 Jan, 2022 |
| 13 | Gary Katz | Director | 7,712 | 0 | 7,712 | 0.0% | 06 Jan, 2023 |
| 14 | Richard H Repetto | Director | 3,046 | 0 | 3,046 | 0.0% | 26 Jan, 2026 |
| 15 | Lori A Conkling | Director | 2,559 | 0 | 2,559 | 0.0% | 02 Sep, 2026 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 31 Jul, 2026 | Earl H Nemser | Vice Chairman | Acquired A | 803,568 | $87.99 | $70.71Mn | 803,568 | Indirect |
| 03 Aug, 2026 | Lori A Conkling | Director | Acquired P | 25 | $87.03 | $2.18K | 2,534 | Direct |
| 01 Jul, 2026 | Lori A Conkling | Director | Acquired P | 25 | $88.03 | $2.20K | 2,509 | Direct |
| 01 Jun, 2026 | Lori A Conkling | Director | Acquired P | 25 | $86.10 | $2.15K | 2,484 | Direct |
| 08 May, 2026 | Earl H Nemser | Vice Chairman | Disposed F | 22,486 | $84.42 | $1.90Mn | 429,344 | Direct |
| 08 May, 2026 | Thomas Aj Frank | Executive Vice President | Disposed F | 31,730 | $84.42 | $2.68Mn | 251,518 | Direct |
| 08 May, 2026 | Denis Mendonca | Chief Accounting Officer | Disposed F | 11,157 | $84.42 | $941.87K | 145,071 | Direct |
| 08 May, 2026 | Milan Galik | Chief Executive Officer | Disposed F | 255,039 | $84.42 | $21.53Mn | 3,215,389 | Direct |
| 08 May, 2026 | Paul Jonathan Brody | Chief Financial Officer | Disposed F | 82,920 | $84.42 | $7.00Mn | 2,856,806 | Direct |
| 28 Apr, 2026 | Lawrence E Harris | Director | Disposed S | 26,000 | $76.93 | $2.00Mn | 173,482 | Direct |
| 01 Apr, 2026 | Lori A Conkling | Director | Acquired P | 25 | $68.38 | $1.71K | 2,434 | Direct |
| 25 Feb, 2026 | Lori A Conkling | Director | Acquired P | 50 | $73.21 | $3.66K | 2,384 | Direct |
| 02 Mar, 2026 | Lori A Conkling | Director | Acquired P | 25 | $69.21 | $1.73K | 2,409 | Direct |
| 26 Jan, 2026 | Earl H Nemser | Vice Chairman | Disposed S | 60,882 | $75.83 | $4.62Mn | 94,118 | Indirect |
| 26 Jan, 2026 | Earl H Nemser | Vice Chairman | Disposed S | 30,817 | $76.72 | $2.36Mn | 63,301 | Indirect |
| 26 Jan, 2026 | Earl H Nemser | Vice Chairman | Disposed S | 3,101 | $77.98 | $241.82K | 60,200 | Indirect |
| 27 Jan, 2026 | Earl H Nemser | Vice Chairman | Disposed S | 39,731 | $75.07 | $2.98Mn | 20,469 | Indirect |
| 27 Jan, 2026 | Earl H Nemser | Vice Chairman | Disposed S | 20,469 | $75.75 | $1.55Mn | 0 | Indirect |
| 01 Jan, 2026 | William Peterffy | Director | Acquired A | 389 | $64.31 | $25.02K | 10,126 | Direct |
| 01 Jan, 2026 | Paul Jonathan Brody | Chief Financial Officer | Acquired A | 389 | $64.31 | $25.02K | 2,939,726 | Direct |