Commitments, Contingencies And Guarantees	3 Months Ended
Mar. 31, 2026
Commitments, Contingencies And Guarantees [Abstract]
Commitments, Contingencies And Guarantees	13. Commitments, Contingencies and Guarantees Legal, Regulatory and Governmental Matters The Company is subject to certain pending and threatened legal, regulatory and governmental actions and proceedings that arise out of the normal course of business. Given the inherent difficulty of predicting the outcome of such matters, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages, the Company is generally not able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of their final resolution or the ultimate settlement. Management believes that the resolution of these matters will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period. The Company accounts for potential losses related to litigation in accordance with FASB ASC Topic 450, “Contingencies.” As of March 31, 2026 and 2025, accruals for potential losses related to legal, regulatory and governmental actions and proceedings matters were not material. Class Action Matter On December 18, 2015, a former individual customer filed a purported class action complaint against IB LLC, IBG, Inc., and Thomas Frank, Ph.D., the Company’s Executive Vice President and former Chief Information Officer, in the U.S. District Court for the District of Connecticut. The complaint alleged that a purported class of IB LLC’s customers were harmed by alleged “flaws” in the computerized system used to close out (i.e., liquidate) positions in customer brokerage accounts that have margin deficiencies. The complaint sought, among other things, undefined compensatory damages and declaratory and injunctive relief. On September 28, 2016, the District Court issued an order granting the Company’s motion to dismiss the complaint in its entirety, without leave to amend. On September 28, 2017, the plaintiff appealed to the United States Court of Appeals for the Second Circuit. On September 26, 2018, the Court of Appeals affirmed the dismissal of plaintiff’s claims of breach of contract and commercially unreasonable liquidation but remanded plaintiff’s claims for negligence back to the District Court. The Company’s motion to dismiss plaintiff’s subsequent amended complaint was denied on September 30, 2019. The Company’s answer and counterclaim were filed on July 26, 2022. On August 25, 2023, the Court granted plaintiff’s motion for class certification, certifying a class that consists of IB LLC account holders who are U.S. residents (with some exclusions) who had positions liquidated during the period of December 18, 2013 to the date of trial at prices outside of a “pricing corridor” defined in the Court’s decision. On August 15, 2025, the parties disclosed to the District Court that a settlement in principle had been reached. On January 20, 2026, the parties signed a class action settlement agreement, which received preliminary approval from the District Court on January 27, 2026. Under the terms of the settlement agreement, the Company will pay up to $5 million to the class and IB LLC will forgive approximately $1.8 million of debts owed by certain class members, with no admission of liability, in exchange for a release of claims. Final payment and debt forgiveness amounts are subject to certain class member opt-outs from the settlement. The Court's fairness hearing for the settlement is scheduled for June 17, 2026. Guarantees Certain of the operating subsidiaries provide guarantees to securities and commodities clearing houses and exchanges which meet the accounting definition of a guarantee under FASB ASC Topic 460, “Guarantees.” Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the operating subsidiaries’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these operating subsidiaries to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements. In connection with its retail brokerage business, IB LLC or other brokerage operating subsidiaries perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective operating subsidiary must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations. Other Commitments Certain clearing houses, clearing banks and firms used by certain operating subsidiaries are given a security interest in certain assets of those operating subsidiaries held by those clearing organizations. These assets may be applied to satisfy the obligations of those operating subsidiaries to the respective clearing organizations.

Commitments, Contingencies And Guarantees

3 Months Ended

Mar. 31, 2026

Commitments, Contingencies And Guarantees [Abstract]

Commitments, Contingencies And Guarantees

13. Commitments, Contingencies and Guarantees

Legal, Regulatory and Governmental Matters

The Company is subject to certain pending and threatened legal, regulatory and governmental actions and proceedings that arise out of the normal course of business. Given the inherent difficulty of predicting the outcome of such matters, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages, the Company is generally not able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of their final resolution or the ultimate settlement. Management believes that the resolution of these matters will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period.

The Company accounts for potential losses related to litigation in accordance with FASB ASC Topic 450, “Contingencies.” As of March 31, 2026 and 2025, accruals for potential losses related to legal, regulatory and governmental actions and proceedings matters were not material.

Class Action Matter

On December 18, 2015, a former individual customer filed a purported class action complaint against IB LLC, IBG, Inc., and Thomas Frank, Ph.D., the Company’s Executive Vice President and former Chief Information Officer, in the U.S. District Court for the District of Connecticut. The complaint alleged that a purported class of IB LLC’s customers were harmed by alleged “flaws” in the computerized system used to close out (i.e., liquidate) positions in customer brokerage accounts that have margin deficiencies. The complaint sought, among other things, undefined compensatory damages and declaratory and injunctive relief.

On September 28, 2016, the District Court issued an order granting the Company’s motion to dismiss the complaint in its entirety, without leave to amend. On September 28, 2017, the plaintiff appealed to the United States Court of Appeals for the Second Circuit. On September 26, 2018, the Court of Appeals affirmed the dismissal of plaintiff’s claims of breach of contract and commercially unreasonable liquidation but remanded plaintiff’s claims for negligence back to the District Court. The Company’s motion to dismiss plaintiff’s subsequent amended complaint was denied on September 30, 2019. The Company’s answer and counterclaim were filed on July 26, 2022. On August 25, 2023, the Court granted plaintiff’s motion for class certification, certifying a class that consists of IB LLC account holders who are U.S. residents (with some exclusions) who had positions liquidated during the period of December 18, 2013 to the date of trial at prices outside of a “pricing corridor” defined in the Court’s decision.

On August 15, 2025, the parties disclosed to the District Court that a settlement in principle had been reached. On January 20, 2026, the parties signed a class action settlement agreement, which received preliminary approval from the District Court on January 27, 2026. Under the terms of the settlement agreement, the Company will pay up to $5 million to the class and IB LLC will forgive approximately $1.8 million of debts owed by certain class members, with no admission of liability, in exchange for a release of claims. Final payment and debt forgiveness amounts are subject to certain class member opt-outs from the settlement. The Court's fairness hearing for the settlement is scheduled for June 17, 2026.

Guarantees

Certain of the operating subsidiaries provide guarantees to securities and commodities clearing houses and exchanges which meet the accounting definition of a guarantee under FASB ASC Topic 460, “Guarantees.” Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the operating subsidiaries’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these operating subsidiaries to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements.

In connection with its retail brokerage business, IB LLC or other brokerage operating subsidiaries perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective operating subsidiary must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations.

Other Commitments

Certain clearing houses, clearing banks and firms used by certain operating subsidiaries are given a security interest in certain assets of those operating subsidiaries held by those clearing organizations. These assets may be applied to satisfy the obligations of those operating subsidiaries to the respective clearing organizations.