Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark one) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2025 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-41232 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) (State or Other Jurisdiction of Incorporation or Organization) (I ...

Core Insights - The discussion highlights the appeal of FDIC insurance among small depositors, emphasizing the importance of digital engagement for banks to retain customers [1] - The conversation also points to the ongoing trend of mergers and acquisitions (M&A) in the banking sector, driven by the need for digital capabilities and the integration of AI technologies [1] Company Insights - North Shore Trust & Savings Bank, now NSTS Bancorp, is identified as a small bank with a high equity to asset ratio of 29 and trades at 70% of tangible book value, making it an attractive investment opportunity [2][3] - RBB Bancorp, a Korean bank based in Los Angeles, is trading at 77% of book value, offering a 3% dividend and maintaining a 12 equity to asset ratio, indicating potential value for investors [4]

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark one) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2025 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-41232 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) Delaware 87-2522769 (State or Other Jurisdiction of (I.R ...

FORM 10-Q (Mark one) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) Delaware 87-2522769 (State or Other Jurisdiction of (I.R.S. Employer Incorporation or Organization) Identification Number) 700 S. Lewis Ave. Waukegan, Illinois 60085 (Address of principal ...

Group 1 - NSTS Bancorp, Inc. announced the appointment of Mr. John S. Pucin to its Board of Directors, filling a vacancy with a term expiring in 2027 [1] - Mr. Pucin is currently the Senior Vice President and Corporate Counsel for Caine & Weiner Company, Inc., and has extensive legal and management experience [2] - The Company expressed excitement about Mr. Pucin's addition to the board, highlighting his qualifications as a valuable resource [3] Group 2 - As of March 31, 2025, North Shore Trust and Savings, the bank under NSTS Bancorp, had approximately $282.7 million in assets [3] - North Shore Trust and Savings has been serving local communities for over 100 years, maintaining strong relationships with businesses, retail customers, and local municipalities [3]

Financial Performance - For the quarter ended March 31, 2025, the company reported a net loss of $328,000, compared to a net loss of $246,000 for the same period in 2024, indicating an increase in net loss due to higher noninterest expenses [115]. - The company's net interest income for the three months ended March 31, 2025, was $1,831,000, an increase from $1,705,000 in the same period of 2024 [112]. - Net interest income increased by $126,000 to $1.9 million for the quarter ended March 31, 2025, compared to $1.7 million for the same period in 2024 [116]. - Noninterest income increased by $22,000 to $334,000 for the quarter ended March 31, 2025, primarily due to a $33,000 increase in gain on sale of mortgage loans [123]. - Total noninterest expenses rose by $266,000 to $2.53 million for the quarter ended March 31, 2025, mainly due to higher salaries and employee benefits [125]. Asset and Liability Management - Total interest-earning assets rose to $259,919,000 in Q1 2025, compared to $241,740,000 in Q1 2024, showing growth in asset base [112]. - The company's total assets increased to $280,110,000 as of March 31, 2025, up from $261,378,000 as of March 31, 2024 [112]. - Total assets increased by $4.0 million to $282.7 million as of March 31, 2025, driven by an increase in cash and cash equivalents [128]. - Total deposits increased by $3.5 million to $193.7 million at March 31, 2025, largely due to a single large deposit of $3.0 million [135]. - Noninterest-bearing liabilities increased to $19,386,000 in Q1 2025 from $17,159,000 in Q1 2024, reflecting changes in funding structure [112]. Loan Performance - The average yield on loans increased to 5.38% in Q1 2025 from 4.71% in Q1 2024, reflecting improved loan performance [112]. - The average outstanding balance of loans increased by $8.6 million to $133.9 million for the quarter ended March 31, 2025, with an average yield of 5.38%, up 67 basis points [117]. - Non-accrual loans amounted to $263,000 as of March 31, 2025, representing 0.20% of total loans outstanding [139]. - The allowance for credit losses on loans totaled $1.2 million as of March 31, 2025, a decrease of $45,000 from December 31, 2024 [134]. Capital and Equity - Total equity increased by $1.0 million to $77.5 million at March 31, 2025, primarily due to a decrease in unrealized losses on the securities available-for-sale portfolio [136]. - As of March 31, 2025, the company had a Tier 1 capital to average assets ratio of 23.11%, indicating a strong capital position [147]. Cash Flow and Liquidity - Net cash used in operating activities for the three months ended March 31, 2025, was $(2.7) million, compared to $92,000 for the same period in 2024 [145]. - Net cash provided by financing activities was $4.2 million for the three months ended March 31, 2025, down from $9.9 million in 2024 [145]. - Cash flows from investing activities were $2.4 million for the three months ended March 31, 2025, compared to $(5.0) million in 2024, reflecting a decrease in the loan portfolio [145]. - The company is committed to maintaining a strong liquidity position and monitors it daily [146]. Operational Overview - The company operates primarily in Lake County, Illinois, with a focus on residential mortgage loans and has expanded its loan production offices to enhance market reach [105]. - The company had $65.2 million in time deposits scheduled to mature within one year as of March 31, 2025, with expectations to retain a significant portion [146]. - The company had $1.7 million in outstanding commitments to originate loans as of March 31, 2025 [148]. - Total commitments, including unused lines of credit, amounted to $11.1 million as of March 31, 2025 [149]. - The company had the capacity to borrow approximately $74.1 million from the FHLB of Chicago as of March 31, 2025 [143]. - The company had no outstanding balance under its $10.0 million federal funds line of credit with BMO Harris Bank [143].

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark one) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-41232 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) (State or Other Jurisdiction of Incorporation or Organization) (I ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark one) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-41232 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) Delaware 87-2522769 (State or Other Jurisdiction of (I.R.S. ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Table of Contents FORM 10-K (Mark one) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-41232 NSTS BANCORP, INC. (Exact name of the registrant as specified in its charter) (State or Other Jurisdiction of Incorporation or Organization) (I ...

Or (Mark one) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 (Exact name of the registrant as specified in its charter) Delaware 87-2522769 (State or Other Jurisdiction of (I.R.S. Employer Incorporation or Organization) Identifi ...