v3.26.1
Segment Information (Tables)
 6 Months Ended
Jun. 30, 2026
Segment Reporting [Abstract]  
Analysis of underwriting income or loss by segment and reconciliation to net income available to common shareholders
The following tables summarize the Company’s underwriting income or loss by segment, together with a reconciliation of underwriting income or loss to net income available to Arch common shareholders:
Three Months Ended
June 30, 2026
InsuranceReinsuranceMortgageTotal
Gross premiums written (1)$2,603 $3,202 $324 $6,126 
Premiums ceded (1)(670)(1,358)(52)(2,077)
Net premiums written1,933 1,844 272 4,049 
Change in unearned premiums(53)(24)13 (64)
Net premiums earned1,880 1,820 285 3,985 
Other underwriting income (2)15 37 5 57 
Losses and loss adjustment expenses(1,185)(992)(19)(2,196)
Acquisition expenses(375)(341)(2)(718)
Other operating expenses (3)(308)(114)(49)(471)
Underwriting income (loss)$27 $410 $220 657 
Net investment income417 
Net realized gains (losses)(17)
Equity in net income of investments accounted for using the equity method196 
Other income (loss)30 
Corporate expenses (4)(12)
Transaction costs and other (4)(32)
Amortization of intangible assets(30)
Interest expense(44)
Net foreign exchange gains (losses)10 
Income (loss) before income taxes and income (loss) from operating affiliates1,175 
Income tax (expense) benefit(164)
Income (loss) from operating affiliates46 
Net income (loss) available to Arch1,057 
Preferred dividends(10)
Net income (loss) available to Arch common shareholders$1,047 
Underwriting Ratios
Loss ratio63.0 %54.6 %6.5 %55.1 %
Acquisition expense ratio19.9 %18.7 %0.9 %18.0 %
Other operating expense ratio (5)15.6 %4.2 %15.4 %10.4 %
Combined ratio98.5 %77.5 %22.8 %83.5 %
Goodwill and intangible assets$747 $91 $325 $1,163 
(1)    Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.
(2)    ‘Other underwriting income’ includes revenue earned from underwriting-related activities covered under existing service contracts.
(3)    ‘Other operating expenses’ primarily include expenses that are related to compensation and employee benefits, information technology and professional fees.
(4)    Certain expenses have been excluded from ‘Corporate expenses’ and reflected in ‘Transaction costs and other.’
(5)    The ‘Other operating expense ratio’ includes ‘Other underwriting income.’
Three Months Ended
June 30, 2025
InsuranceReinsuranceMortgageTotal
Gross premiums written (1)$2,681 $3,196 $323 $6,196 
Premiums ceded (1)(645)(1,137)(70)(1,848)
Net premiums written2,036 2,059 253 4,348 
Change in unearned premiums(67)28 28 (11)
Net premiums earned1,969 2,087 281 4,337 
Other underwriting income (2)13 46 3 62 
Losses and loss adjustment expenses(1,178)(1,128)3 (2,303)
Acquisition expenses(387)(436)(1)(824)
Other operating expenses (3)(288)(118)(48)(454)
Underwriting income (loss)$129 $451 $238 818 
Net investment income405 
Net realized gains (losses)229 
Equity in net income of investments accounted for using the equity method162 
Other income (loss)18 
Corporate expenses (4)(29)
Transaction costs and other (4)(18)
Amortization of intangible assets(48)
Interest expense(38)
Net foreign exchange gains (losses)(88)
Income (loss) before income taxes and income (loss) from operating affiliates1,411 
Income tax (expense) benefit(214)
Income (loss) from operating affiliates40 
Net income (loss) available to Arch1,237 
Preferred dividends(10)
Net income (loss) available to Arch common shareholders$1,227 
Underwriting Ratios
Loss ratio59.8 %54.1 %(1.2)%53.1 %
Acquisition expense ratio19.6 %20.9 %0.4 %19.0 %
Other operating expense ratio (5)14.0 %3.5 %16.0 %9.1 %
Combined ratio93.4 %78.5 %15.2 %81.2 %
Goodwill and intangible assets$875 $105 $339 $1,319 

(1)    Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.
(2)    ‘Other underwriting income’ includes revenue earned from underwriting-related activities covered under existing service contracts.
(3)    ‘Other operating expenses’ primarily include expenses that are related to compensation and employee benefits, information technology and professional fees.
(4)    Certain expenses have been excluded from ‘Corporate expenses’ and reflected in ‘Transaction costs and other.’
(5)    The ‘Other operating expense ratio’ includes ‘Other underwriting income.’
Six Months Ended
June 30, 2026
InsuranceReinsuranceMortgageTotal
Gross premiums written (1)$5,300 $6,616 $640 $12,551 
Premiums ceded (1)(1,461)(2,596)(102)(4,154)
Net premiums written3,839 4,020 538 8,397 
Change in unearned premiums(88)(369)31 (426)
Net premiums earned3,751 3,651 569 7,971 
Other underwriting income (2)26 74 16 116 
Losses and loss adjustment expenses(2,311)(1,940)(34)(4,285)
Acquisition expenses(750)(688)(10)(1,448)
Other operating expenses (3)(623)(246)(100)(969)
Underwriting income (loss)$93 $851 $441 1,385 
Net investment income825 
Net realized gains (losses)(104)
Equity in net income of investments accounted for using the equity method356 
Other income (loss)25 
Corporate expenses (4)(43)
Transaction costs and other (4)(50)
Amortization of intangible assets(60)
Interest expense(81)
Net foreign exchange gains (losses)31 
Income (loss) before income taxes and income (loss) from operating affiliates2,284 
Income tax (expense) benefit(262)
Income (loss) from operating affiliates82 
Net income (loss) available to Arch2,104 
Preferred dividends(20)
Net income (loss) available to Arch common shareholders$2,084 
Underwriting Ratios
Loss ratio61.6 %53.1 %5.9 %53.8 %
Acquisition expense ratio20.0 %18.8 %1.9 %18.2 %
Other operating expense ratio (5)15.9 %4.7 %14.8 %10.7 %
Combined ratio97.5 %76.6 %22.6 %82.7 %

(1)    Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.
(2)    ‘Other underwriting income’ includes revenue earned from underwriting-related activities covered under existing service contracts.
(3)    ‘Other operating expenses’ primarily include expenses that are related to compensation and employee benefits, information technology and professional fees.
(4)    Certain expenses have been excluded from ‘Corporate expenses’ and reflected in ‘Transaction costs and other.’
(5)    The ‘Other operating expense ratio’ includes ‘Other underwriting income.’
Six Months Ended
June 30, 2025
InsuranceReinsuranceMortgageTotal
Gross premiums written (1)$5,326 $6,690 $649 $12,659 
Premiums ceded (1)(1,357)(2,315)(130)(3,796)
Net premiums written3,969 4,375 519 8,863 
Change in unearned premiums(140)(260)62 (338)
Net premiums earned3,829 4,115 581 8,525 
Other underwriting income (2)16 85 14 115 
Losses and loss adjustment expenses(2,406)(2,484)— (4,890)
Acquisition expenses(730)(853)(5)(1,588)
Other operating expenses (3)(582)(245)(100)(927)
Underwriting income (loss)$127 $618 $490 1,235 
Net investment income783 
Net realized gains (losses)232 
Equity in net income of investments accounted for using the equity method215 
Other income (loss)16 
Corporate expenses (4)(79)
Transaction costs and other (4)(28)
Amortization of intangible assets(97)
Interest expense(73)
Net foreign exchange gains (losses)(115)
Income (loss) before income taxes and income (loss) from operating affiliates2,089 
Income tax (expense) benefit(335)
Income (loss) from operating affiliates57 
Net income (loss) available to Arch1,811 
Preferred dividends(20)
Net income (loss) available to Arch common shareholders$1,791 
Underwriting Ratios
Loss ratio62.8 %60.4 %— %57.4 %
Acquisition expense ratio19.1 %20.7 %0.9 %18.6 %
Other operating expense ratio (5)14.8 %3.9 %14.9 %9.5 %
Combined ratio96.7 %85.0 %15.8 %85.5 %

(1)    Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.
(2)    ‘Other underwriting income’ includes revenue earned from underwriting-related activities covered under existing service contracts.
(3)    ‘Other operating expenses’ primarily include expenses that are related to compensation and employee benefits, information technology and professional fees.
(4)    Certain expenses have been excluded from ‘Corporate expenses’ and reflected in ‘Transaction costs and other.’
(5)    The ‘Other operating expense ratio’ includes ‘Other underwriting income.’