Financial Position - Total assets increased by $9.2 million, or 3.8%, to $248.0 million at December 31, 2025, from $238.8 million at June 30, 2025[168]. - Total stockholders' equity increased by $1.2 million to $46.9 million at December 31, 2025, primarily due to net income of $946,000[176]. - Total deposits increased by $3.1 million, or 1.8%, to $178.4 million at December 31, 2025, mainly due to a $6.0 million increase in demand, NOW, and money market deposits, or 12.6%[175]. - FHLB advances increased by $4.0 million to $19.0 million at December 31, 2025, due to new borrowings during the six months ended December 31, 2025[176]. - Total debt securities available for sale decreased by $1.1 million, or 21.9%, to $4.1 million at December 31, 2025, due to maturing or called securities[170]. Loan Portfolio - Loans increased by $11.1 million, or 5.5%, contributing to the overall asset growth[168]. - Gross loans increased by $11.1 million, or 5.5%, to $213.7 million at December 31, 2025, driven by a $7.7 million increase in one-to-four-family residential loans, or 13.6%, and a $3.9 million increase in multi-family real estate loans, or 8.1%[171]. - The allowance for credit losses at December 31, 2025, reflects the company's estimate of lifetime credit losses expected from its loan portfolio[157]. - The allowance for credit losses was $1.7 million, or 0.80% of loans outstanding at December 31, 2025, compared to $1.7 million, or 0.92%, at December 31, 2024[196]. - The allowance for credit losses allocated to one-to-four-family residential loans was $1,100,000 at December 31, 2025, accounting for 64.6% of the total allowance[236]. Income and Expenses - Net income for the three months ended December 31, 2025, was $501,000, an increase of $450,000, or 880.7%, from $51,000 for the same period in 2024[186]. - Net interest income for the six months ended December 31, 2025, was $4.011 million, with a net interest rate spread of 3.11%[182]. - Interest income increased by $683,000, or 35.3%, to $3.0 million for the three months ended December 31, 2025, compared to $2.3 million for the same period in 2024[187]. - Non-interest income slightly increased by $10,000 to $190,000 for the three months ended December 31, 2025, from $180,000 for the same period in 2024[199]. - Total non-interest expenses were $1.6 million for the three months ended December 31, 2025, an increase of $100,000, or 6.6%, from $1.5 million for the same period in 2024[201]. Credit Losses and Provisions - The provision for credit losses for the three months ended December 31, 2025, was $33,000, compared to $8,000 for the same period in 2024, reflecting an increase in the loan portfolio[195]. - A hypothetical change in the allowance for credit losses could result in an increase of $182,000, or 10.9%, based on adjustments to economic parameters[160]. - The company assesses the allowance for credit losses quarterly, considering historical loan loss experience and current economic conditions[150]. - The company may adjust its allowance for credit losses based on regulatory reviews and changes in economic conditions[162]. - The total non-performing loans to total loans ratio rose to 0.09% at December 31, 2025, up from 0.03% at June 30, 2025[224]. Cash Flow and Liquidity - Net cash provided by operating activities was $1.9 million for the six months ended December 31, 2025, compared to $1.1 million for the same period in 2024[239]. - Net cash used in investing activities was $9.8 million for the six months ended December 31, 2025, compared to $7.2 million provided in 2024[239]. - Net cash provided by financing activities was $7.1 million for the six months ended December 31, 2025, compared to $2.6 million used in 2024[239]. - The company monitors its liquidity position daily and expects to meet current funding commitments[240]. - The primary impact of inflation on operations is reflected in increased operating costs, with interest rates having a more significant impact on performance[245]. Regulatory and Compliance - Marathon Bank was classified as "well capitalized" for regulatory capital purposes as of December 31, 2025[241]. - The company intends to leverage the benefits of the JOBS Act, potentially delaying the adoption of new accounting standards[155]. - The company enters into various contractual obligations, including data processing services and operating leases[243]. - The company anticipates retaining a substantial portion of maturing time deposits and may utilize additional borrowings if necessary[240].

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ 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 For the transition period from ________ to ________ Commission File Number: 001-42608 MARATHON BANCORP, INC. (Exact name of registrant as specified in its charter) | Maryland | 8 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended June 30, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission File Number: 001-42608 MARATHON BANCORP, INC. | (Exact name of registrant as specified in its charter) | | --- | | Maryland 86-2 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission File Number: 001-42608 MARATHON BANCORP, INC. (Exact name of registrant as specified in its charter) | Maryland | 86-21 ...

Financial Position - Total assets decreased by $1.3 million, or 0.6%, to $217.9 million at December 31, 2024, from $219.2 million at June 30, 2024[162]. - Net loans decreased by $6.5 million, or 3.6%, contributing to the overall asset decline[162]. - Cash and cash equivalents increased by $5.7 million, or 54.4%, to $16.2 million at December 31, 2024, primarily due to a decrease in net loans[163]. - Total debt securities available for sale decreased by $364,000, or 5.5%, from $6.6 million at June 30, 2024, to $6.2 million at December 31, 2024[164]. - The decrease in debt securities was primarily related to municipal bond calls of $240,000[164]. - Gross loans decreased by $6.7 million, or 3.6%, to $178.6 million at December 31, 2024, from $185.3 million at June 30, 2024[165]. - Total deposits increased slightly by $436,000, or 0.3%, to $173.4 million at December 31, 2024, from $173.0 million at June 30, 2024[169]. - FHLB advances decreased by $3.0 million to $10.0 million at December 31, 2024, compared to $13.0 million at June 30, 2024[170]. - Total stockholders' equity increased by $390,000 due to net income of $226,000 and a decrease in accumulated other comprehensive loss of $118,000[171]. Income and Expenses - Net income for the three months ended December 31, 2024, was $51,000, a decrease of $221,000, or 81.2%, from $272,000 in the same period of 2023[180]. - Interest income decreased by $135,000, or 5.6%, to $2.3 million for the three months ended December 31, 2024, compared to $2.4 million for the same period in 2023[181]. - Loan interest income decreased by $152,000, or 6.9%, to $2.0 million for the three months ended December 31, 2024, due to a decrease in the average balance of the loan portfolio[182]. - Net interest income decreased by $80,000, or 5.4%, to $1.4 million for the three months ended December 31, 2024[189]. - Non-interest income increased by $3,000 to $180,000 for the three months ended December 31, 2024, from $177,000 in the same period of 2023[196]. - Total non-interest expenses were $1.5 million for the three months ended December 31, 2024, compared to $1.6 million for the same period in 2023, a decrease of $28,000, or 1.8%[197]. - Non-interest income declined by $31,000, or 7.7%, to $374,000 for the six months ended December 31, 2024, primarily due to a decrease in mortgage banking income[216]. - Total non-interest expenses increased by $62,000, or 2.1%, to $3.1 million for the six months ended December 31, 2024, driven by higher salaries and occupancy costs[219]. Credit Losses and Allowances - The allowance for credit losses (ACL) at December 31, 2024, represents the company's current estimate of lifetime credit losses expected from its loan portfolio[152]. - The company assesses the allowance for credit losses on a quarterly basis to maintain a reasonable level to absorb expected credit losses[144]. - The allowance for credit losses was $1.7 million, or 0.92%, of loans outstanding at December 31, 2024[193]. - Provision for credit losses was recorded at $8,000 for the three months ended December 31, 2024, compared to a recovery of $135,000 in the same period of 2023[192]. - The allowance for credit losses was $1.7 million, or 0.92% of loans outstanding at December 31, 2024, down from $1.9 million, or 0.96%, at December 31, 2023[213]. - The provision for credit losses for the three months ended December 31, 2024, was $8,000, compared to a recovery of $135,000 in the same period of the previous year[237]. - The total charge-offs for the period were $0, with total recoveries of $1,000, leading to net recoveries of $1,000[237]. - The company foreclosed on collateral supporting a construction loan valued at $2.1 million, resulting in a provision adjustment[226]. Cash Flow and Capital - Net cash provided by operating activities for the six months ended December 31, 2024, was $1.1 million, an increase from $990,000 for the same period in 2023[242]. - Net cash provided by investing activities increased to $7.2 million for the six months ended December 31, 2024, compared to $1.3 million in 2023[242]. - Net cash used in financing activities decreased to $2.6 million for the six months ended December 31, 2024, down from $5.9 million in 2023[242]. - The bank was classified as "well capitalized" for regulatory capital purposes as of December 31, 2024[244]. - The bank anticipates retaining a substantial portion of maturing time deposits, which may mitigate the need for additional borrowings[243]. Loan Portfolio and Performance - Average outstanding loans for the three months ended December 31, 2024, were $175.7 million with a yield of 4.68%[173]. - Total interest-earning assets decreased to $197.7 million with a net interest margin of 2.85% for the three months ended December 31, 2024[173]. - The net interest rate spread for the six months ended December 31, 2024, was 2.47%[176]. - The average balance of the loan portfolio decreased by $19.8 million, or 10.2%, to $175.7 million for the three months ended December 31, 2024[184]. - The average yield on loans increased by 19 basis points to 4.65% for the six months ended December 31, 2024, compared to 4.46% for the same period in 2023[203]. - The average balance of deposits decreased by $16.9 million, or 10.0%, to $151.6 million for the six months ended December 31, 2024[206]. - Total non-performing assets amounted to $1.4 million as of December 31, 2024, consistent with the previous period[226]. - The total non-performing assets to total assets ratio was 0.64% for both December 31, 2024, and June 30, 2024[226]. - There were no loans classified as substandard, doubtful, or loss in the company's loan portfolio as of December 31, 2024[229]. - The company expects a small recovery related to a settlement of litigation concerning a property in the quarter ending March 31, 2025[228].

Table of Contents As filed with the Securities and Exchange Commission on February 6, 2025 Registration No. 333-283805 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 PRE-EFFECTIVE AMENDMENT NO. 1 TO THE FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Marathon Bancorp, Inc. and Marathon Bank 401(k) Plan (Exact Name of Registrant as Specified in Its Charter) (State or other jurisdiction of (Primary Standard Industrial (I.R.S. Employer incorporation or organization) Cl ...

As filed with the Securities and Exchange Commission on December 13, 2024 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 Table of Contents FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Marathon Bancorp, Inc. and Marathon Bank 401(k) Plan (Exact Name of Registrant as Specified in Its Charter) (State or other jurisdiction of (Primary Standard Industrial (I.R.S. Employer incorporation or organization) Classification Code Number) Identification N ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission File Number: 000-56269 MARATHON BANCORP, INC. (Exact name of registrant as specified in its charter) | Maryland | 8 ...

Financial Performance - Net interest income decreased to $5.840 million for the year ended June 30, 2024, down from $6.700 million in 2023, reflecting a decrease of 12.8%[275] - Non-interest income fell to $726,000 in 2024, down from $1.301 million in 2023, a decrease of 44.3%[275] - The efficiency ratio increased to 106.64% in 2024, compared to 73.54% in 2023, indicating a decline in operational efficiency[275] - The return on average assets decreased to (0.08)% in 2024, down from 0.71% in 2023, indicating a decline in profitability[275] - Net loss for the year ended June 30, 2024, was $187,000, a decrease of $1.9 million, or 111.2%, from net income of $1.7 million for the year ended June 30, 2023[290] Asset and Liability Changes - Total assets decreased from $238,779,000 in 2023 to $219,234,000 in 2024, a decline of approximately 8.5%[271] - Loans receivable, net decreased from $197,714,000 in 2023 to $183,448,000 in 2024, representing a reduction of about 7.2%[271] - Deposits decreased from $197,254,000 in 2023 to $172,981,000 in 2024, a decrease of approximately 12.3%[271] - Cash, cash equivalents, and interest-bearing deposits in other financial institutions decreased from $15,537,000 in 2023 to $10,672,000 in 2024, a decline of about 31.5%[271] - Total assets decreased by $19.6 million, or 8.2%, to $219.2 million at June 30, 2024, from $238.8 million at June 30, 2023[275] - Total deposits decreased by $24.3 million, or 12.3%, to $173.0 million at June 30, 2024, compared to $197.3 million at June 30, 2023[280] - Gross loans decreased by $14.6 million, or 7.3%, to $185.3 million at June 30, 2024, from $199.9 million at June 30, 2023[278] Funding and Borrowings - Federal Home Loan Bank (FHLB) advances increased from $8,000,000 in 2023 to $13,000,000 in 2024, an increase of 62.5%[271] - FHLB advances increased by $5.0 million to $13.0 million at June 30, 2024, compared to $8.0 million in 2023, to support funding needs[281] - Interest paid on FHLB borrowings increased by $545,000 to $648,000 for the year ended June 30, 2024, due to a higher average balance and rate on borrowings[296] - As of June 30, 2024, the company had a $79.5 million line of credit with the Federal Home Loan Bank of Chicago, with $13.0 million in borrowings outstanding[309] Income and Expenses - Interest income increased by $453,000, or 5.0%, to $9.4 million for the year ended June 30, 2024, compared to $9.0 million for the year ended June 30, 2023[291] - Loan interest income rose by $455,000, or 5.6%, to $8.6 million for the year ended June 30, 2024, with an average yield increase of 28 basis points to 4.46%[292] - Interest expense increased by $1.3 million, or 57.6%, to $3.6 million for the year ended June 30, 2024, driven by a $766,000 increase in interest on deposits[294] - Total non-interest expenses increased to $7.0 million for the year ended June 30, 2024, compared to $5.9 million for the year ended June 30, 2023, largely due to a $1.0 million increase in expenses related to foreclosed assets[307] - Non-interest income decreased by $576,000 to $726,000 for the year ended June 30, 2024, primarily due to the absence of gains from life insurance and foreclosed assets[303] Credit Losses and Allowances - The allowance for credit losses on loans is based on management's estimates of expected credit losses over the contractual term of loans[255] - The evaluation of credit losses includes qualitative assessments of economic conditions expected over a 24-month period[256] - The allowance for credit losses was $1.8 million, or 0.97%, of loans outstanding at June 30, 2024, down from $2.2 million, or 1.08%, at June 30, 2023[300] Tax and Cash Flow - Income tax benefit for the year ended June 30, 2024, was $59,000, a decrease of $504,000 compared to an expense of $445,000 for the year ended June 30, 2023, primarily due to a decrease in income before taxes of $2.4 million[308] - Net cash provided by operating activities was $417,000 for the year ended June 30, 2024, down from $2.0 million for the year ended June 30, 2023[311] - Net cash provided by investing activities was $17.7 million for the year ended June 30, 2024, compared to $14.4 million used in investing activities for the year ended June 30, 2023[311] - Net cash used in financing activities was $19.4 million for the year ended June 30, 2024, compared to $15.8 million provided by financing activities for the year ended June 30, 2023[311] Capital and Commitments - The company was classified as "well capitalized" for regulatory capital purposes as of June 30, 2024[313] - Outstanding commitments to originate loans were $1.3 million, and commitments to sell loans were $418,000 as of June 30, 2024[314] - Time deposits scheduled to mature in one year or less totaled $44.8 million as of June 30, 2024, with expectations of substantial renewal[314] Accounting and Valuation - The company did not record a cumulative-effect adjustment related to its available-for-sale securities upon adoption of CECL on July 1, 2023[266] - The fair value of certain assets is determined in accordance with FASB Accounting Standards Codification Topic 820, which prioritizes valuation inputs into three levels[270] - The company eliminated its state net deferred tax asset balances as of July 1, 2023, resulting in deferred tax expense of approximately $112,000 for the year ended June 30, 2024[308] Economic Impact - The primary impact of inflation on operations is reflected in increased operating costs, with interest rates having a more significant impact on performance than inflation[317]

Financial Position - Total assets decreased by $13.0 million, or 5.4%, to $225.8 million at March 31, 2024, from $238.8 million at June 30, 2023[173]. - Cash and cash equivalents decreased by $3.7 million, or 31.4%, to $8.1 million at March 31, 2024, primarily due to a decrease in total deposits of $27.6 million[174]. - Total debt securities available for sale decreased by $2.0 million, or 22.4%, to $6.9 million at March 31, 2024, primarily due to the call of $1.5 million in corporate bonds[175]. - Total deposits decreased by $27.6 million, or 14.0%, to $169.7 million at March 31, 2024, from $197.3 million at June 30, 2023, with certificates of deposit decreasing by $17.7 million, or 21.1%[178]. - Total stockholders' equity remained unchanged at $31.3 million from June 30, 2023, to March 31, 2024[180]. Loan Performance - Net loans decreased by $5.8 million, or 2.9%, at March 31, 2024[173]. - Gross loans decreased by $6.2 million, or 3.1%, to $193.7 million at March 31, 2024, from $199.9 million at June 30, 2023, with consumer loans down by $1.3 million, or 44.3%[176]. - The allowance for credit losses was $1.8 million, or 0.91%, of loans outstanding at March 31, 2024, down from $2.1 million, or 1.01%, at March 31, 2023[199]. - The total non-performing loans to total loans ratio is 0.03% as of March 31, 2024, indicating a stable credit quality compared to previous periods[230]. - The allowance to non-performing loans ratio is 3,160.71% as of March 31, 2024, highlighting a strong coverage of non-performing loans[240]. Income and Expenses - Net loss for the three months ended March 31, 2024 was $631,000, a decrease of $997,000, or 272.6%, from net income of $366,000 for the same period in 2023[190]. - Interest income increased by $35,000, or 1.5%, to $2.3 million for the three months ended March 31, 2024, primarily due to an increase in loan interest income of $70,000[191]. - Interest expense increased by $279,000, or 43.9%, to $916,000, driven by a $73,000 increase in interest paid on deposits and a $206,000 increase in interest paid on borrowings[193]. - Non-interest income decreased by $112,000 to $147,000, primarily due to a lack of gains from life insurance death benefits compared to $88,000 in the prior year[202]. - Total non-interest expenses increased by $1,023,000, or 68.9%, to $2.5 million, largely due to a $970,000 increase in expenses associated with foreclosed assets[203]. Credit Losses and Provisions - The recovery of credit losses was $216,000 for the nine months ended March 31, 2024, compared to no provision for credit losses in the same period of 2023[215]. - The provision for credit losses for the three months ended March 31, 2024, was a recovery of $122,000, contrasting with no provision in the same period last year[240]. - The allowance for credit losses allocated to real estate loans is not specified, but the overall allowance reflects management's assessment of potential future losses[241]. Cash Flow and Financing - Net cash provided by operating activities for the nine months ended March 31, 2024, was $188,000, a significant decrease from $1.3 million for the same period in 2023[245]. - Net cash used in financing activities was $12.6 million for the nine months ended March 31, 2024, compared to $16.6 million provided in the same period of 2023[245]. - At March 31, 2024, the bank had a $82.0 million line of credit with the Federal Home Loan Bank of Chicago, with $23.0 million in borrowings outstanding[243]. Regulatory and Economic Factors - The company is subject to various risks including changes in economic conditions and competition among financial institutions[151]. - The effective tax rate increased to 24.3% for the three months ended March 31, 2024, compared to 13.7% for the same period in 2023[204]. - The impact of inflation on operations is primarily reflected in increased operating costs, with interest rates having a more significant effect on performance[252].