Reserve for Loss and Loss Expense

9 Months Ended

Sep. 30, 2024

The table below provides a roll forward of the reserve for loss and loss expense for beginning and ending reserve balances:


	Nine Months ended September 30,
($ in thousands)	2024		2023
Gross reserve for loss and loss expense, at beginning of period	$	5,336,911	5,144,821
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of period	618,601		757,513
Net reserve for loss and loss expense, at beginning of period	4,718,310		4,387,308
Incurred loss and loss expense for claims occurring in the:
Current year	2,212,750		1,865,247
Prior years	182,748		(5,782)
Total incurred loss and loss expense	2,395,498		1,859,465
Paid loss and loss expense for claims occurring in the:
Current year	638,494		607,595
Prior years	1,053,299		988,859
Total paid loss and loss expense	1,691,793		1,596,454
Net reserve for loss and loss expense, at end of period	5,422,015		4,650,319
Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period	1,029,981		651,051
Gross reserve for loss and loss expense, at end of period	$	6,451,996	5,301,370

The increase in the net reserve for loss and loss expense at September 30, 2024 compared to December 31, 2023, primarily reflected (i) net unfavorable prior year reserve development, (ii) higher catastrophe losses in Nine Months 2024, (iii) exposure increases due to premium growth, and (iv) elevated loss cost trends for the current accident year.

Prior year reserve development in Nine Months 2024 was unfavorable by $182.7 million, consisting of $211.0 million of unfavorable casualty reserve development, partially offset by $28.3 million of favorable property reserve development. The unfavorable casualty reserve development was driven by our Standard Commercial Lines segment, which included (i) $216.0 million in our general liability line of business, primarily driven by increased severities in accident years 2020 through 2023, and (ii) $20.0 million in our commercial automobile line of business, partially offset by favorable development of (iii) $20.0 million in our workers compensation line of business and (iv) $5.0 million in our bonds line of business.

Additionally, in our Standard Personal Lines segment, we had unfavorable casualty reserve development of $5.0 million in our personal automobile line of business, offset by favorable development of $5.0 million in our homeowners line of business.

Prior year reserve development in Nine Months 2023 was favorable by $5.8 million, consisting of $16.5 million of favorable casualty reserve development, partially offset by $10.7 million of unfavorable property reserve development. The favorable casualty reserve development included $24.5 million in our workers compensation line of business and $5.0 million in our Excess and Surplus ("E&S") casualty lines of business, partially offset by $9.0 million of unfavorable casualty reserve development in our personal automobile line of business and $4.0 million in our commercial automobile line of business.