v3.26.1
Fair value measurements (Tables)
 6 Months Ended
Jun. 30, 2026
Fair Value Disclosures [Abstract]  
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis by Level
Our financial assets and liabilities measured at fair value on a recurring basis by level were as follows:
June 30, 2026
(in millions)Quoted prices in active markets for identical assets
Level 1		Significant other observable
Level 2		Significant unobservable inputs
Level 3		Estimated fair value
Fixed maturity and short-term investments measured at fair value:
Corporate$— $228.8 $— $228.8 
US government and agency— 130.6 — 130.6 
Non-US government and agency— 225.7 — 225.7 
Residential mortgage-backed— 54.1 — 54.1 
Commercial mortgage-backed— 7.7 — 7.7 
Other asset-backed securities— 15.3 — 15.3 
Total fixed maturity and short-term investments$— $662.2 $— $662.2 
    
December 31, 2025
(in millions)Quoted prices in active markets for identical assets
Level 1		Significant other observable
Level 2		Significant unobservable inputs
Level 3		Estimated fair value
Fixed maturity and short-term investments measured at fair value:
Corporate$— $246.9 $— $246.9 
US government and agency— 124.5 — 124.5 
Non-US government and agency— 248.1 — 248.1 
Residential mortgage-backed— 55.6 — 55.6 
Commercial mortgage-backed— 15.0 — 15.0 
Other asset-backed securities— 21.9 — 21.9 
Total fixed maturity and short-term investments$— $712.0 $— $712.0 
Schedule of Assets Measured at Fair Value on Non-Recurring Basis
The following table presents assets measured at fair value on a non-recurring basis:
June 30, 2026
(in millions)Quoted prices in active markets for identical assets
Level 1		Significant other observable
Level 2		Significant unobservable inputs
Level 3		Estimated fair value
Assets measured at fair value:
Other investments:
MGAs and TPAs$— $— $78.9 $78.9 
Venture funds— — 9.2 9.2 
Total$— $— $88.1 $88.1 
December 31, 2025
(in millions)Quoted prices in active markets for identical assets
Level 1		Significant other observable
Level 2		Significant unobservable inputs
Level 3		Estimated fair value
Assets measured at fair value:
Other investments:
MGAs$— $— $59.9 $59.9 
Venture funds— — 24.1 24.1 
Total$— $— $84.0 $84.0