The Corporation conducted its most recent annual impairment testing in May 2026, utilizing a qualitative assessment. Based on this assessment, management concluded that it is more likely than not that the estimated fair value exceeded the carrying value (including goodwill) for each reporting unit. Therefore, a step one quantitative analysis was not required. There have been no events since the May 2026 impairment test that have changed the Corporation's impairment assessment conclusion. There were no impairment charges recorded in the first nine months of 2025 or 2026.

The Corporation has CDIs which are amortized. CDI recorded as part of the American National acquisition is amortized over ten years using the sum of digits method while prior acquisitions are amortized under the straight line method. Changes in the gross carrying amount, accumulated amortization, and net book value for CDIs were as follows:


(in thousands)	Nine Months Ended Sep 30, 2026		Year Ended Dec 31, 2025
Core deposit intangibles
Gross carrying amount at the beginning of period	$	88,109	$	88,109
Additions during the period	103,200		—
Accumulated amortization	(81,250)		(65,260)
Net book value	$	110,059	$	22,849
Amortization during the period	$	15,990	$	8,811


(in thousands)	Nine Months Ended Sep 30, 2026			Year Ended Dec 31, 2025
Mortgage servicing rights
Mortgage servicing rights at beginning of period	$	86,337		$	87,683
Additions	9,391			8,716
Decay	(7,479)			(8,621)
Valuation:

Changes in fair value of asset	6,670			(1,441)


Mortgage servicing rights at end of period	$	94,919		$	86,337





Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)	$	6,164,126		$	6,191,012
Mortgage servicing rights to servicing portfolio	1.54		%	1.39		%

The projections of amortization expense for CDIs and decay for MSRs are based on existing asset balances, the current interest rate environment, and prepayment speeds as of September 30, 2026. The actual expense the Corporation recognizes in any given period may be significantly different depending upon acquisition or sale activities, changes in interest rates, prepayment speeds, market conditions, regulatory requirements, and events or circumstances that indicate the carrying amount of an asset may not be recoverable. The following table shows the estimated future yearly amortization expense for CDIs and decay for MSRs:


(in thousands)	Core Deposit Intangibles		Mortgage Servicing Rights
Three Months Ended December 31, 2026	$	6,894	$	2,157
2027	26,167		11,051
2028	18,965		12,226
2029	15,285		11,773
2030	11,788		11,137
2031	9,851		10,368
Beyond 2031	21,109		36,207
Total estimated amortization expense and MSRs decay(a)	$	110,059	$	94,919

(a) Includes the decrease in value due to passage of time, including the impact from both regularly scheduled principal payments and partial loan paydowns.