Commitments and Contingencies	6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Senior Notes On June 9, 2026, Arch Capital completed a public offering of $600 million aggregate principal amount of 5.250% senior notes due 2036 (the “2036 Notes”) and $1.4 billion aggregate principal amount of 5.950% senior notes due 2056, (the “2056 Notes” and, together with the 2036 Notes, the “Notes”). The Notes are senior unsecured obligations of Arch Capital and rank equally with all of its existing and future senior unsecured indebtedness. Interest payments on the Notes are due semi-annually in arrears on June 15 and December 15, beginning on December 15, 2026, to holders of record on the preceding June 1 and December 1, as the case may be. Subject to conditions of redemption, Arch Capital may redeem all or any portion of the 2036 Notes and 2056 Notes at any time and from time to time (i) prior to March 15, 2036 and December 15, 2055, respectively, at a redemption price equal to the “make-whole” redemption price for the notes to be redeemed, plus accrued and unpaid interest thereon to, but excluding, the redemption date; and (ii) on or after March 15, 2036 and December 15, 2055, respectively, at a redemption price for the notes to be redeemed equal to 100% of the principal amount of such notes, plus accrued and unpaid interest to, but excluding, the redemption date. Arch Capital used a portion of the net proceeds of the Notes to purchase the Tender Offer notes validly tendered (and not withdrawn), as described below, and intends to use the remaining net proceeds to redeem, repurchase, repay or otherwise retire the existing 4.011% Senior Notes due in 2026 and use the balance for general corporate purposes. Tender Offers On June 2, 2026, Arch Capital announced the commencement of cash tender offers (the “Tender Offers”) by Arch Capital Group (U.S.) Inc. (“Arch-U.S.”) of its outstanding 5.144% Senior Notes due 2043 (the “2043 Notes”) and Arch Capital Finance LLC (“Arch Finance”) of its outstanding 5.031% Senior Notes due 2046 (the “2046 Notes”). Upon expiration of the Tender Offers, Arch-U.S. repurchased $218.7 million aggregate principal amount of the 2043 Notes and Arch Finance repurchased $199.1 million aggregate principal amount of the 2046 Notes, which resulted in a pre-tax gain of $16 million. Interest Paid Interest paid on the Company’s senior notes and other borrowings was $65 million for the six months ended June 30, 2026, compared to $64 million for the 2025 period. Investment Commitments The Company’s investment commitments, which are primarily related to agreements entered into by the Company to invest in funds and separately managed accounts when called upon, were approximately $4.4 billion at June 30, 2026, compared to $3.7 billion at December 31, 2025.

On June 9, 2026, Arch Capital completed a public offering of $600 million aggregate principal amount of 5.250% senior notes due 2036 (the “2036 Notes”) and $1.4 billion aggregate principal amount of 5.950% senior notes due 2056, (the “2056 Notes” and, together with the 2036 Notes, the “Notes”). The Notes are senior unsecured obligations of Arch Capital and rank equally with all of its existing and future senior unsecured indebtedness. Interest payments on the Notes are due semi-annually in arrears on June 15 and December 15, beginning on December 15, 2026, to holders of record on the preceding June 1 and December 1, as the case may be. Subject to conditions of redemption, Arch Capital may redeem all or any portion of the 2036 Notes and 2056 Notes at any time and from time to time (i) prior to March 15, 2036 and December 15, 2055, respectively, at a redemption price equal to the “make-whole” redemption price for the notes to be redeemed, plus accrued and unpaid interest thereon to, but excluding, the redemption date; and (ii) on or after March 15, 2036 and December 15, 2055, respectively, at a redemption price for the notes to be redeemed equal to 100% of the principal amount of such notes, plus accrued and unpaid interest to, but excluding, the redemption date.

Arch Capital used a portion of the net proceeds of the Notes to purchase the Tender Offer notes validly tendered (and not withdrawn), as described below, and intends to use the remaining net proceeds to redeem, repurchase, repay or otherwise retire the existing 4.011% Senior Notes due in 2026 and use the balance for general corporate purposes.

On June 2, 2026, Arch Capital announced the commencement of cash tender offers (the “Tender Offers”) by Arch Capital Group (U.S.) Inc. (“Arch-U.S.”) of its outstanding 5.144% Senior Notes due 2043 (the “2043 Notes”) and Arch Capital Finance LLC (“Arch Finance”) of its outstanding 5.031% Senior Notes due 2046 (the “2046 Notes”). Upon expiration of the Tender Offers, Arch-U.S. repurchased $218.7 million aggregate principal amount of the 2043 Notes and Arch Finance repurchased $199.1 million aggregate principal amount of the 2046 Notes, which resulted in a pre-tax gain of $16 million.

The Company’s investment commitments, which are primarily related to agreements entered into by the Company to invest in funds and separately managed accounts when called upon, were approximately $4.4 billion at June 30, 2026, compared to $3.7 billion at December 31, 2025.