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Arch PRESS RELEASE NASDAQ Symbol : ACGL For Immediate Release July 28 , 2021 EXHIBIT 99.1 Arch Capital Group Ltd. Waterloo House , Ground Floor 100 Pitts Bay Road Pembroke HM 08 Bermuda ARCH CAPITAL GROUP LTD . REPORTS 2021 SECOND QUARTER RESULTS PEMBROKE , BERMUDA -- ( BUSINESS WIRE ) -- Arch Capital Group Ltd. ( NASDAQ : ACGL ) announces its 2021 second quarter results . The results included : Net income available to Arch common shareholders of $ 663.8 million , or $ 1.63 per share , a 21.2 % annualized return on average common equity , compared to $ 288.4 million , or $ 0.71 per share , for the 2020 second quarter ; After - tax operating income available to Arch common shareholders ( ¹ ) of $ 407.2 million , or $ 1.00 per share , a 13.0 % annualized return on average common equity , compared to $ 16.6 million , or $ 0.04 per share , for the 2020 second quarter ; Pre - tax current accident year catastrophic losses for the Company's insurance and reinsurance segments , net of reinsurance and reinstatement premiums ( ¹ ) of $ 46.5 million , including $ 0.9 million of COVID - 19 related losses ; Favorable development in prior year loss reserves , net of related adjustments ( ¹ ) of $ 64.8 million ; Combined ratio excluding catastrophic activity and prior year development ( ¹ ) of 80.7 % , compared to 89.7 % for the 2020 second quarter ; The percentage of loans in default on U.S. primary mortgage business was 3.11 % at June 30 , 2021 , compared to 3.86 % at March 31 , 2021 ; Total return on investments ( ¹ ) of 1.58 % ; 7.8 million shares repurchased at an aggregate cost of $ 306.0 million ; Book value per common share of $ 32.02 at June 30 , 2021 , a 4.8 % increase from March 31 , 2021 and a 15.9 % increase from June 30 , 2020 . All earnings per share amounts discussed in this release are on a diluted basis . The following table summarizes the Company's underwriting results , both ( i ) on a consolidated basis and ( ii ) on a consolidated basis excluding the ' other ' segment ( i.e. , results of Watford ) : ( U.S. dollars in thousands ) Gross premiums written Net premiums written Net premiums earned Underwriting income Underwriting Ratios Loss ratio Underwriting expense ratio Combined ratio Combined ratio excluding catastrophic activity and prior year development ( 1 ) Consolidated Three Months Ended June 30 , $ 2021 3,286,291 2,399,524 2,120,909 2020 % Change 2021 Consolidated Excluding ' Other ' Segment ( ¹ ) Three Months Ended June 30 , 2020 % Change S 2,317,692 41.8 $ 3,117,505 $ 2,206,410 41.3 1,668,311 43.8 2,224,133 1,562,455 42.3 1,665,354 27.4 1,936,672 1,533,819 26.3 386,521 ( 22,539 ) n / m 395,387 ( 13,410 ) n / m % Point Change % Point Change 54.7 % 73.9 % ( 19.2 ) 52.6 % 27.3 % 27.9 % 82.0 % 101.8 % ( 0.6 ) ( 19.8 ) 27.2 % 79.8 % 73.4 % 27.8 % ( 20.8 ) ( 0.6 ) 101.2 % ( 21.4 ) 80.7 % 89.7 % ( 1 ) Presentation represents a " non - GAAP " financial measure as defined in Regulation G. Such presentation excludes the results of Watford Holdings Ltd. ( " Watford " ) . Pursuant to GAAP , the Company consolidates the results of Watford in its financial statements , although it only owned approximately 10 % of Watford's outstanding common equity as of June 30 , 2021. See ' Comments on Regulation G ' for further details . 1 ( 9.0 )