Item 5. OTHER INFORMATION

Rule 10b5-1 Trading Plans

The following table discloses the adoption of Rule 10b5-1 trading plans for the sale of shares of our common stock by our directors and officers (as defined in Rule 16a-1(f) under the Securities Exchange Act of 1934, as amended) during the three months ended September 30, 2024, each of which is intended to satisfy the affirmative defense conditions of Rule 10b-51(c) under the Exchange Act.

(1)The later of 90 days or two days after the Company’s filing of its Form 10-Q for the quarter ended June 30,2025, or upon the earlier completion of all authorized transactions under the plan.

(2)Shares held through Conyers Investments LLC, which is indirectly wholly owned by Thomas Peterffy. Mr. Peterffy is also a manager of Conyers Investments LLC with the unilateral power to vote or sell the shares.

Other than as disclosed above, no other director or officer adopted, modified or terminated a contract, instruction or written plan for the purchase or sale of our securities intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or a “non-Rule 10b5-1 trading arrangement”, as defined in Item 408(c) of Regulation S-K.

Other

On April 15, 2025, the Company announced its intention to effect a four-for-one forward split of its common stock in the form of a stock dividend to make stock ownership more accessible to investors. On April 14, 2025 and on April 22, 2025, respectively, the Company’s Board of Directors and the Company’s majority stockholder approved by written consent an amendment to Interactive Brokers Group, Inc.’s Amended and Restated Certificate of Incorporation to, among other things, increase the number of authorized shares of common stock to accommodate the stock split.

Each record holder of common stock as of the close of market on Monday, June 16, 2025, will receive three additional shares of common stock, to be distributed after the close of market on Tuesday, June 17, 2025. Trading is expected to commence on a split-adjusted basis at market open on Wednesday, June 18, 2025.

On April 15, 2025, the Company also declared an increase in the quarterly cash dividend from $0.25 to $0.32 per common share, payable on June 13, 2025, to stockholders of record as of May 30, 2025. The Company currently intends to pay quarterly dividends of $0.08 (on a post-stock split basis) per common share to our common stockholders for the foreseeable future

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