| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Nemser Earl H | Vice Chairman, Director | ONE PICKWICK PLAZA, GREENWICH | /s/ Raymond Bussiere as authorized signatory for Earl H Nemser | 07 Jan 2026 | 0001391400 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | IBKR | Class A common stock | Award | $0 | +23,240 | +5.4% | $0.000000 | 451,052 | 31 Dec 2025 | Direct | F1, F2 |
| transaction | IBKR | Class A common stock | Award | $25,017 | +389 | +0.09% | $64.31 | 451,441 | 31 Dec 2025 | Direct | F2, F3, F4 |
| holding | IBKR | Class A common stock | 400,000 | 31 Dec 2025 | by EN Holdings LLC | F5 |
| Id | Content |
|---|---|
| F1 | This represents a grant of restricted stock units under the 2007 Stock Incentive Plan as amended ("Plan") that will vest 20% on or about 5/9/2026 and 20% on each of the first four anniversaries of 5/9/2026. |
| F2 | This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the Plan and (b) unvested restricted stock units that were awarded under the Plan. |
| F3 | This represents an annual grant of restricted stock units under the Plan for being a member of the issuer's Board of Directors, which vested immediately on 12/31/2025. |
| F4 | The price represents the closing price of the issuer's Class A common stock on December 31, 2025. |
| F5 | Represents number of securities owned by EN Holdings LLC, which is owned by the Reporting Person and his affiliates. |