NSTS Bancorp, Inc. Quarterly report [Sections 13 or 15(d)]

Note 6 - Fair Value Measurements - Fair Value On Recurring Basis (Details)

Note 6 - Fair Value Measurements - Fair Value On Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Securities available for sale	$ 76,717	$ 78,719
US Treasury Notes Securities [Member]
Securities available for sale	7,051	7,085
US Government Agencies Debt Securities [Member]
Securities available for sale	8,243	8,534
Municipal Bonds [Member]
Securities available for sale	11,936	12,146
Residential Mortgage-Backed Securities [Member]
Securities available for sale	22,789	23,769
Fair Value, Recurring [Member]
Securities available for sale	76,717	78,719
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	7,051	7,085
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	69,666	71,634
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| US Treasury Notes Securities [Member]
Securities available for sale	7,051	7,085
Fair Value, Recurring [Member] \| US Treasury Notes Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	7,051	7,085
Fair Value, Recurring [Member] \| US Treasury Notes Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| US Treasury Notes Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member]
Securities available for sale	8,243	8,534
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	8,243	8,534
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Municipal Bonds [Member]
Securities available for sale	11,936	12,146
Fair Value, Recurring [Member] \| Municipal Bonds [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Municipal Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	11,936	12,146
Fair Value, Recurring [Member] \| Municipal Bonds [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member]
Securities available for sale	22,789	23,769
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	22,789	23,769
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Collateralized Mortgage Obligations [Member]
Securities available for sale	26,698	27,185
Fair Value, Recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale	0	0
Fair Value, Recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale	26,698	27,185
Fair Value, Recurring [Member] \| Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale	$ 0	$ 0