Securities are classified as AFS on the consolidated balance sheets at the time of purchase. AFS securities include those securities that the Company intends to hold for an indefinite period of time, but not necessarily to maturity, and are carried at fair value on the consolidated balance sheets. Premiums and discounts on investment securities are amortized or accreted into interest income over the estimated life of the related securities using the effective interest method.


	June 30, 2025
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Securities AFS:
U.S. Treasury securities	$	18,194	$	—	$	1,274	$	16,920
U.S. government agency securities	4,724		—		23		4,701
State, county and municipals	296,965		86		23,095		273,956
Mortgage-backed securities	496,460		3,085		26,243		473,302
Corporate debt securities	84,446		22		4,094		80,374
Total securities AFS	$	900,789	$	3,193	$	54,729	$	849,253


	December 31, 2024
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Securities AFS:
U.S. Treasury securities	$	15,795	$	—	$	1,767	$	14,028
U.S. government agency securities	5,563		—		43		5,520
State, county and municipals	310,931		116		26,344		284,703
Mortgage-backed securities	455,386		1,101		34,534		421,953
Corporate debt securities	85,183		—		4,972		80,211
Total securities AFS	$	872,858	$	1,217	$	67,660	$	806,415


	Six Months Ended June 30,
(in thousands)	2025		2024
Securities AFS:
Gross gains	$	4	$	1,038
Gross losses	—		(70)
Gains (losses) on sales of securities AFS, net	$	4	$	968
Proceeds from sales of securities AFS	$	1,250	$	4,987

All mortgage-backed securities included in the securities portfolio were issued by U.S. government agencies and corporations. Investment securities with a carrying value of $434 million and $355 million, as of June 30, 2025 and December 31, 2024, respectively, were pledged as collateral to secure public deposits and borrowings, as applicable, and for liquidity or other purposes as required by regulation. Accrued interest on investment securities totaled $5 million at both June 30, 2025 and December 31, 2024, and is included in accrued interest receivable and other assets on the consolidated balance sheets.

The following table presents gross unrealized losses and the related estimated fair value of investment securities for which an allowance for credit losses has not been recorded, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position.


	June 30, 2025
	Less than 12 months				12 months or more				Total
($ in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Number of Securities
Securities AFS:
U.S. Treasury securities	$	2,492	$	3	$	14,428	$	1,271	$	16,920	$	1,274	2
U.S. government agency securities	1,425		1		3,276		22		4,701		23		10
State, county and municipals	30,179		1,239		229,545		21,856		259,724		23,095		493
Mortgage-backed securities	32,243		387		239,566		25,856		271,809		26,243		389
Corporate debt securities	4,320		36		66,428		4,058		70,748		4,094		45
Total	$	70,659	$	1,666	$	553,243	$	53,063	$	623,902	$	54,729	939


	December 31, 2024
	Less than 12 months				12 months or more				Total
($ in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Number of Securities
Securities AFS:
U.S. Treasury securities	$	—	$	—	$	14,028	$	1,767	$	14,028	$	1,767	1
U.S. government agency securities	1,918		11		3,602		32		5,520		43		10
State, county and municipals	43,565		1,497		228,355		24,847		271,920		26,344		528
Mortgage-backed securities	79,899		1,105		252,612		33,429		332,511		34,534		429
Corporate debt securities	7,048		63		68,332		4,909		75,380		4,972		50
Total	$	132,430	$	2,676	$	566,929	$	64,984	$	699,359	$	67,660	1,018

As of June 30, 2025 and December 31, 2024, no allowance for credit losses on AFS securities was recognized. The Company does not consider its securities AFS with unrealized losses to be attributable to credit-related factors, as the unrealized losses in each category have occurred as a result of changes in noncredit-related factors such as changes in interest rates, market spreads and market conditions subsequent to purchase, not credit deterioration. Furthermore, the Company does not have the intent to sell any of these AFS securities and believes that it is more likely than not that we will not have to sell any such securities before a recovery of cost.

The amortized cost and fair value of investment securities by contractual maturity are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties; as this is particularly inherent in mortgage-backed securities, these securities are not included in the maturity categories below.


As of June 30, 2025	Securities AFS
(in thousands)	Amortized Cost		Fair Value
Due in less than one year	$	23,977	$	23,753
Due in one year through five years	151,304		142,637
Due after five years through ten years	147,467		136,131
Due after ten years	81,581		73,430
	404,329		375,951
Mortgage-backed securities	496,460		473,302
Total investment securities	$	900,789	$	849,253

Other investments include “restricted” equity securities, equity securities with readily determinable fair values, and private company securities. As a member of the Federal Reserve Bank System and the Federal Home Loan Bank (“FHLB”) System, Nicolet is required to maintain an investment in the capital stock of these entities. These equity securities are “restricted” in that they can only be sold back to the respective institutions or another member institution at par. Therefore, they are less liquid than other exchange traded equity securities. As no ready market exists for these stocks, and they have no quoted market value, these investments are carried at cost. Also included are investments in other private companies that do not have quoted market prices, which are carried at cost less impairment charges, if any. The carrying value of other investments are summarized as follows.


	June 30, 2025		December 31, 2024
(in thousands)	Amount		Amount
Federal Reserve Bank stock	$	33,425	$	33,335
Federal Home Loan Bank (“FHLB”) stock	6,290		9,674
Equity securities with readily determinable fair values	8,456		8,610
Other investments	11,423		10,506
Total other investments	$	59,594	$	62,125