NBT BANCORP INC

September 30, 2026

1. Description of Business

NBT Bancorp Inc. is a registered financial holding company incorporated in the state of Delaware in 1986, with its principal headquarters located in Norwich, New York. The principal assets of NBT Bancorp Inc. consist of all of the outstanding shares of common stock of its subsidiaries, including: NBT Bank, National Association (the “Bank”), NBT Financial Services, Inc. (“NBT Financial”), NBT Holdings, Inc. (“NBT Holdings”), CNBF Capital Trust I, NBT Statutory Trust I, NBT Statutory Trust II, Alliance Financial Capital Trust I, Alliance Financial Capital Trust II and Evans Capital Trust I (collectively, the “Trusts”). The principal sources of revenue for NBT Bancorp Inc. are the management fees and dividends it receives from the Bank, NBT Financial and NBT Holdings. Collectively, NBT Bancorp Inc. and its subsidiaries are referred to herein as (the “Company”).

The Company’s business, primarily conducted through the Bank, consists of providing commercial banking, retail banking and wealth management services primarily to customers in its market area, which includes upstate New York, northeastern Pennsylvania, southern New Hampshire, western Massachusetts, Vermont, southern Maine and central and northwestern Connecticut. The Company has been, and intends to remain, a community-oriented financial institution offering a variety of financial services. The Company’s business philosophy is to operate as a community bank with local decision-making, providing a broad array of banking and financial services to retail, commercial and municipal customers.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited interim consolidated financial statements include the accounts of NBT Bancorp Inc. and its wholly-owned subsidiaries mentioned above. In the opinion of management, the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods in accordance with U.S. generally accepted accounting principles (“GAAP”) and in accordance with the instructions for the Quarterly Report on Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). Accordingly, the consolidated financial statements do not include all of the information and notes necessary for complete financial statements in conformity with GAAP. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2025 Annual Report on Form 10-K. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. All material intercompany transactions have been eliminated in consolidation. Amounts previously reported in the consolidated financial statements are reclassified whenever necessary to conform to current period presentation. The Company has evaluated subsequent events for potential recognition and/or disclosure, and none were identified.

Use of Estimates in the Preparation of Financial Statements

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results may differ from those estimates and such differences could be material to the financial statements. Estimates associated with the allowance for credit losses are particularly susceptible to material changes in the near term.

3. Recent Accounting Pronouncements

Recently Adopted Accounting Standards

In November 2025, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2025-08,Financial Instruments-Credit Losses (Topic 326): Purchased Loans. The ASU expands the population of acquired financial assets subject to the gross-up approach in Topic 326, Financial Instrument-Credit Losses. In accordance with the amendments in this update, loans acquired without credit deterioration and deemed seasoned are purchased seasoned loans and accounted for using the gross-up approach at acquisition. The amendments apply prospectively and will be effective for fiscal periods beginning after December 15, 2026. The Company elected to early-adopt the ASU as of January 1, 2026.

Accounting Standards Issued Not Yet Adopted

In November 2024, the FASB issued ASU 2024-03,Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, that addresses longstanding investor requests for more information regarding expenses included in the expense captions presented on the face of the income statement. The ASU will require a tabular disclosure that disaggregates certain income statement expenses including employee compensation, depreciation and intangible asset amortization. In January 2025, the FASB issued ASU 2025-01,Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date, which revises the effective date of ASU 2024-03. The ASU will become effective in the annual reporting periods beginning after December 15, 2026, and early adoption is permitted. Aside from complying with the new disclosure requirements, the adoption is not expected to have a material impact on the consolidated financial statements.

In December 2025, the FASB issued ASU 2025-11,Interim Reporting (Topic 270): Narrow-Scope Improvements, which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. The ASU provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years, with early adoption permitted. Aside from complying with the new disclosure requirements, the adoption is not expected to have a material impact on the consolidated financial statements.

4. Acquisitions

Evans Bancorp, Inc.

On May 2, 2025, the Company completed the acquisition of Evans Bancorp, Inc. (“Evans”)through the merger of Evans with and into the Company, with the Company surviving the merger. Total consideration for the acquisition was $221.8 million in common stock. Evans, with assets of $2.19 billion at December 31, 2024, was headquartered in Williamsville, New York. Its primary subsidiary, Evans Bank, National Association (“Evans Bank”), was a federally-chartered national banking association operating 18 banking locations in Western New York. The acquisition enhances the Company’s presence in Western New York, including the Buffalo and Rochester communities. In connection with the acquisition, the Company issued 5.1 million shares of common stock and acquired approximately $131.2 million of identifiable net assets. Preliminary goodwill of $91.4 million was recognized as a result of the merger and is not amortizable or deductible for tax purposes. During the fourth quarter of 2025, the Company revised the accrued income taxes and deferred taxes associated with the Evans acquisition, which resulted in a $0.8 million decrease in goodwill. Total goodwill of $90.6 million was recognized as a result of the merger. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since May 2, 2025. As a result of the full integration of the operations of Evans, it is not practicable to determine all revenue or net income included in the Company’s operating results relating to Evans since the date of acquisition as Evans results cannot be separately identified.

The acquisition of Evans is being accounted for as a business combination in accordance with Accounting Standards Codification (“ASC”) 805, “Business Combinations” (“ASC 805”), using the acquisition method of accounting. Accordingly, as of the date of the acquisition, the Company recorded the assets acquired, liabilities assumed and consideration paid at fair value based on management’s best estimates using information available at the date of the acquisition. These estimates were subject to adjustment based on updated information not available at the time of the acquisition and all amounts have now been finalized. The amount of goodwill arising from the acquisition consists largely of the synergies and economies of scale expected from combining the operations of the Company with Evans.

The following table summarizes the estimated fair value of the assets acquired and liabilities assumed:

The following is a description of the valuation methodologies used to estimate the fair values of major categories of assets acquired and liabilities assumed. The Company used an independent valuation specialist to assist with the determination of fair values for certain acquired assets and assumed liabilities.

Cash and due from banks - The estimated fair value was determined to approximate the carrying amount of these assets.

Securities available for sale (“AFS”) - The estimated fair value of the AFS investment portfolio was primarily determined using quoted market prices and dealer quotes. The investment securities were sold immediately after the merger and no gains or losses were recorded.

Securities held to maturity(“HTM”) - The estimated fair value of the HTM investment portfolio, which consisted of local municipal securities, was retained at par, which is estimated to be equal to fair value.

Loans- The estimated fair value of loans were based on a discounted cash flow methodology applied on a pooled basis. Loans were first segmented by purchased credit deteriorated (“PCD”) or non-purchased credit deteriorated (“non-PCD”) status, and then further grouped according to Federal Deposit Insurance Corporation (“FDIC”) call report segmentation. The valuation considered key loan characteristics including loan type, term, rate, payment schedule and loan performance attributes. Certain key assumptions related to prepayment speeds, probability of default (“PD”), loss given default (“LGD”) and discount rate were also considered. The discount rates applied were based on a build-up approach factoring in the funding mix, servicing costs, liquidity premium and factors related to performance risk.

Core deposit intangible - The core deposit intangible was valued utilizing the cost savings method approach, which recognizes the cost savings represented by the expense of maintaining the core deposit base versus the cost of an alternative funding source. The valuation incorporated assumptions related to account retention, discount rates, deposit interest rates, deposit maintenance costs and alternative funding rates.

Deposits- The fair value of noninterest bearing demand deposits, interest-bearing checking, money market and savings deposit accounts were assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. Certificate of deposit (“CD”) (time deposit accounts) were valued at the present value of the certificates’ expected contractual payments discounted at market rates for similar certificates which approximates carrying value.

Borrowings- The estimated fair value of short-term borrowings was determined to approximate stated value. Long-term debt, subordinated debt and junior subordinated debt were valued using a discounted cash flow approach incorporating a discount rate that incorporated similar terms, maturity and credit rating.

Accounting for Acquired Loans- Acquired loans are classified into two categories: PCD loans and non-PCD loans. PCD loans are defined as a loan or group of loans that have experienced more than insignificant credit deterioration since origination. Non-PCD loans had an allowance established on acquisition date, which is recognized as an expense through the provision for credit losses. For PCD loans, an allowance is recognized by adding it to the fair value of the loan, which is the amortized cost. There is no provision for credit loss expense recognized on PCD loans because the initial allowance is established by grossing-up the amortized cost of the PCD loan. The allowance for credit losses on non-PCD loans of $13.0 million was recorded through the provision for loan losses within the unaudited interim consolidated statements of income. The following table provides details related to the fair value of acquired PCD loans.

The non-PCD loans acquired from Evans had an acquisition date fair value of $1.37 billion, compared to $1.43 billion in gross contractual amounts receivable. At the acquisition date, the Company estimated that $13.0 million of the contractual cash flows were not expected to be collected.

Direct costs related to the acquisition were expensed as incurred. Acquisition integration-related expenses were $1.1 million and $19.5 million during the three and nine months ended September 30, 2025, respectively. These amounts have been separately stated in the unaudited interim consolidated statements of income and are included in operating activities in the unaudited interim consolidated statements of cash flow.

Supplemental Pro Forma Financial Information (Unaudited)

The following table presents certain unaudited pro forma financial information for illustrative purposes only, for the three and nine months ended September 30, 2025, as if Evans had been acquired on January 1, 2025. This unaudited pro forma information combines the historical results of Evans with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition taken place at the beginning of the year prior to the acquisition. The unaudited pro forma information does not consider any changes to the provision expense resulting from recording loan assets at fair value, cost savings or business synergies. As a result, actual amounts would have differed from the unaudited pro forma information presented and the differences could be significant.

5. Securities

The amortized cost, estimated fair value and unrealized gains (losses) of AFS securities are as follows:

There wasno allowance for credit losses on AFS securities as of September 30, 2026 and December 31, 2025.

During the three and nine months ended September 30, 2026 and 2025, there wereno gains or losses reclassified out of accumulated other comprehensive income (loss) (“AOCI”) and into earnings.

The amortized cost, estimated fair value and unrealized gains (losses) of HTM securities are as follows:

At September 30, 2026 and December 31, 2025, all of the mortgage-backed HTM securities were comprised of U.S. government agency and government-sponsored enterprises securities.

The Company recordedno gains from calls on HTM securities for the three and nine months ended September 30, 2026 and 2025.

AFS and HTM securities with amortized costs totaling $1.91 billion at September 30, 2026 and $1.87 billion at December 31, 2025, were pledged to secure public deposits and for other purposes required or permitted by law. Additionally, at September 30, 2026 and December 31, 2025, AFS and HTM securities with an amortized cost of $198.4 million and $207.6 million, respectively, were pledged as collateral for securities sold under repurchase agreements.

The following tables set forth information with regard to gains and (losses) on equity securities:

As of September 30, 2026 and December 31, 2025, the carrying value of equity securities without readily determinable fair values was $1.0 million. The Company performed a qualitative assessment to determine whether the investments were impaired and identified no areas of credit concern as of September 30, 2026 and 2025. There wereno impairments, or downward or upward adjustments recognized for equity securities without readily determinable fair values during the three and nine months ended September 30, 2026 and 2025.

The following table sets forth information with regard to contractual maturities of debt securities at September 30, 2026:

Maturities of mortgage-backed, collateralized mortgage obligations and asset-backed securities are stated based on their estimated average lives. Actual maturities may differ from estimated average lives or contractual maturities because, in certain cases, borrowers have the right to call or prepay obligations, with or without call or prepayment penalties.

Except for U.S. government securities and government-sponsored enterprises securities, there wereno holdings, when taken in the aggregate, of any single issuer that exceeded 10% of consolidated stockholders’ equity at September 30, 2026 and December 31, 2025.

The following table sets forth information with regard to investment securities with unrealized losses, for which an allowance for credit losses has not been recorded, segregated according to the length of time the securities were in a continuous unrealized loss position:

The Company does not believe the AFS securities that were in an unrealized loss position as of September 30, 2026 and December 31, 2025, which consisted of 436 and 350 individual securities, respectively, represented a credit loss impairment. AFS debt securities in unrealized loss positions are evaluated for impairment related to credit losses at least quarterly. As of September 30, 2026 and December 31, 2025, the majority of the AFS securities in an unrealized loss position consisted of debt securities issued by U.S. government agencies or U.S. government-sponsored enterprises that carry the explicit and/or implicit guarantee of the U.S. government, which are widely recognized as “risk-free” and have a long history of zero credit losses. Total gross unrealized losses were primarily attributable to changes in interest rates, relative to when the investment securities were purchased, and not due to the credit quality of the investment securities. The Company does not intend to sell, nor is it more likely than not that the Company will be required to sell the securities before recovery of their amortized cost bases, which may be at maturity. The Company elected to exclude accrued interest receivable (“AIR”) from the amortized cost basis of debt securities. AIR on AFS debt securities totaled $5.7 million and $5.6 million at September 30, 2026 and December 31, 2025, respectively, and is excluded from the estimate of credit losses and reported in theother assets financial statement line.

None of the Bank’s HTM debt securities were past due or on nonaccrual status as of September 30, 2026 and December 31, 2025. There wasno accrued interest reversed against interest income for the three and nine months ended September 30, 2026 or the year ended December 31, 2025 as all securities remained in accrual status. In addition, there wereno collateral-dependent HTM debt securities as of September 30, 2026 and December 31, 2025. There wasno allowance for credit losses on HTM securities as of September 30, 2026 and December 31, 2025. As of September 30, 2026 and December 31, 2025,61% and 65%, respectively, of the Company’s HTM debt securities were issued by U.S. government agencies or U.S. government-sponsored enterprises with bond ratings of A to AAA. These securities carry the explicit and/or implicit guarantee of the U.S. government, which are widely recognized as “risk-free” and have a long history of zero credit losses. Therefore, the Company did not record an allowance for credit losses for these securities as of September 30, 2026 and December 31, 2025. The remaining HTM debt securities at September 30, 2026 and December 31, 2025 were comprised of state and municipal obligations with bond ratings of A to AAA excluding the $155.7 million and $85.7 million, respectively, of local municipal bonds which are not rated. Based on the Company’s current expected credit losses (“CECL”) methodology, the expected credit loss on the HTM municipal bond portfolio was deemed immaterial, therefore no allowance for credit loss was recorded as of September 30, 2026 and December 31, 2025. AIR on HTM debt securities totaled $4.0 million at September 30, 2026 and $3.9 million at December 31, 2025 and is excluded from the estimate of credit losses and reported in theother assets financial statement line.

6. Loans

A summary of loans, net of deferred fees and origination costs, by category(1) isas follows:

(1) Loans are summarized by business line which does not align to how the Company assesses credit risk in the allowance for credit losses under CECL.

Included in the above loans are net deferred loan origination (fees) costs totaling $(23.8) million and $(37.9) million at September 30, 2026 and December 31, 2025, respectively.

7. Allowance for Credit Losses and Credit Quality of Loans

The allowance for credit losses totaled $140.0 million at September 30, 2026, compared to $138.0 million at December 31, 2025. The allowance for credit losses as a percentage of loans was 1.17% at September 30, 2026, compared to 1.19% at December 31, 2025.

The allowance for credit losses calculation incorporated a 6-quarter forecast period to account for forecast economic conditions under each scenario utilized in the measurement. For periods beyond the 6-quarter forecast, the model reverts to long-term economic conditions over a 4-quarter reversion period on a straight-line basis. The Company considers a baseline, upside and downside economic forecast in measuring the allowance. From the second quarter of 2025 through the fourth quarter of 2025, the Company included an additional downside scenario with stagflation conditions, which is characterized as an economic environment where inflation rises alongside unemployment. Stagflation was identified as an emerging risk as tariff policies impacted the economy.

The quantitative model as of September 30, 2026 incorporated a baseline economic outlook along with alternative upside and downside scenarios sourced from a reputable third-party to accommodate other potential economic conditions in the model. At September 30, 2026, the weightings were 60%, 5% and 35% for the baseline, upside and downside economic forecast scenarios, respectively. The baseline outlook reflected an economic environment where the northeast unemployment rate increases from 4.27% in the third quarter of 2026 to 4.74% by the end of the forecast period, with a peak northeast unemployment rate of 4.76% in the fourth quarter of 2027. National Gross Domestic Product (“GDP”) annualized growth (on a quarterly basis) is expected to start the fourth quarter of 2026 at approximately 1.56% and increase to 2.08% by the end of the forecast period. Key assumptions in the baseline economic outlook included the Federal Reserve policy rate of 3.50%-3.75% and the economy remaining at full employment. The alternative upside scenario assumes improved economic conditions from the baseline outlook. Under this scenario, northeast unemployment falls from 4.27% in the third quarter of 2026 to 3.88% in the first quarter of 2027 and eventually settles at 4.01% by the end of the forecast period. The alternative downside scenario with recessionary conditions assumes deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment rises from 4.27% in the third quarter of 2026 to a peak of 7.64% in the fourth quarter of 2027. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of September 30, 2026. Additional qualitative adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools.

The quantitative model as of June 30, 2026 incorporated a baseline economic outlook along with alternative upside and downside scenarios sourced from a reputable third-party to accommodate other potential economic conditions in the model. At June 30, 2026, the weightings were 60%, 5% and 35% for the baseline, upside and downside economic forecast scenarios, respectively. The baseline outlook reflected an economic environment where the northeast unemployment rate increases from 4.46% in the second quarter of 2026 to 4.65% by the end of the forecast period, with a peak northeast unemployment rate of 4.69% in the second quarter of 2027. National GDP annualized growth (on a quarterly basis) is expected to start the third quarter of 2026 at approximately 1.95% and decrease to 1.93% by the end of the forecast period. Key assumptions in the baseline economic outlook included the Federal Reserve policy rate of 3.50%-3.75% and the economy remaining at full employment. The alternative upside scenario assumes improved economic conditions from the baseline outlook. Under this scenario, northeast unemployment falls from 4.46% in the second quarter of 2026 to 3.85% in the third quarter of 2027 and eventually settles at 3.90% by the end of the forecast period. The alternative downside scenario with recessionary conditions assumes deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment rises from 4.46% in the second quarter of 2026 to a peak of 7.81% in the third quarter of 2027. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of June 30, 2026. Additional qualitative adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools.

The quantitative model as of December 31, 2025 incorporated a baseline economic outlook along with alternative upside scenario and two equally weighted downside scenarios, recessionary conditions and stagflation, sourced from a reputable third-party to accommodate other potential economic conditions in the model. At December 31, 2025, the weightings were 65%, 5% and 30% for the baseline, upside and downside economic forecast scenarios, respectively. The baseline outlook reflected an economic environment where the northeast unemployment rate increases from 4.5% in the first quarter of 2026 to 4.8% by the end of the forecast period, with a peak northeast unemployment rate of 4.9% in the fourth quarter of 2026. National GDP annualized growth (on a quarterly basis) is expected to start the first quarter of 2026 at approximately 2.55% and decrease to 1.8% by the end of the forecast period. Key assumptions in the baseline economic outlook included the Federal Reserve cutting rates with one 25 basis point cut at the December meeting and the economy remaining at full employment. The alternative upside scenario assumes improved economic conditions from the baseline outlook. Under this scenario, northeast unemployment falls from 4.4% in the fourth quarter of 2025 to 4.0% in the second quarter of 2026 and eventually settles at 4.1% by the end of the forecast period. The alternative downside scenario with recessionary conditions assumes deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment rises from 4.4% in the fourth quarter of 2025 to a peak of 7.8% in the first quarter of 2027. The alternative downside stagflation scenario assumes deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment rises from 4.4% in the fourth quarter of 2025 to 6% by the end of the forecast period in the second quarter of 2027, with a peak northeast unemployment rate of 8.2% in the first quarter of 2028. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of December 31, 2025. Additional qualitative adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools, reversion adjustments for the stagflation scenario and recent trends in asset value indices. Additional monitoring for industry concentrations, loan growth and policy exceptions was also conducted.

There wereno loans purchased with credit deterioration during the three and nine months ended September 30, 2026. There were $336.4 million of PCD loans acquired from Evans during the year ended December 31, 2025, which resulted in an allowance for credit losses at acquisition of $7.7 million. During the nine months ended September 30, 2026, the Company purchased $10.7 million of residential loans at a 4.6% premium with a $114 thousand allowance for credit losses recorded for these loans. During 2025, the Company purchased $21.3 million of residential loans at a 4.5% premium with a $234 thousand allowance for credit losses recorded for these loans.

The Company made a policy election to report AIR in theother assets line item on the consolidated balance sheets. AIR on loans totaled $42.6 million at September 30, 2026 and $42.5 million at December 31, 2025 and withno estimated allowance for credit losses related to AIR at September 30, 2026 and December 31, 2025 as it is excluded from amortized cost.

The following tables present the activity in the allowance for credit losses by our portfolio segments:

The allowance for credit losses as of September 30, 2026 increased compared to December 31, 2025 and September 30, 2025 primarily due to providing for current year loan growth, change in scenario weightings and the establishment of specific reserves during the nine months ended September 30, 2026 for newly identified individually evaluated loans. These increases to the allowance for credit losses were partially offset by improvements in the economic forecast, model adjustment, accelerated prepayment speeds and changes in loan composition and balances, including reductions in other consumer and residential solar portfolios. First quarter 2026 model adjustments lowered the allowance, as updates from the annual model review and recalibration process incorporated recent delinquency and loss experience which reflected improved default estimates across most portfolio segments.

Individually Evaluated Loans

The threshold for evaluating commercial loans risk graded substandard or doubtful, and nonperforming loans specifically evaluated for individual credit loss is $1.0 million. As of September 30, 2026, nine relationships were identified for individual credit loss evaluation with an amortized cost basis of $34.0 million, with $5.0 million of allowance for credit loss. As of September 30, 2026, there were $20.8 million of loans in nonaccrual status that were specifically evaluated for individual credit loss withno allowance for credit loss as the fair value of the underlying collateral supported the amortized cost. As of December 31, 2025, five relationships with an amortized cost basis of $12.2 million were identified for individual credit loss evaluation. These relationships were in nonaccrual status and withno allowance for credit loss as the fair value of the underlying collateral supported the amortized cost.

The following table sets forth information with regard to past due and nonperforming loans by loan segment:

Credit Quality Indicators

The Company has developed an internal loan grading system to evaluate and quantify the Company’s loan portfolio with respect to quality and risk, focusing on, among other things, borrower’s financial strength, experience and depth of borrower’s management, primary and secondary sources of repayment, payment history, nature of the business and industry outlook. The internal grading system enables the Company to monitor the quality of the entire loan portfolio on a consistent basis and provide management with an early warning system, which facilitates recognition of and response to problem loans and potential problem loans.

Commercial Grading System

For Commercial & Industrial (“C&I”) and Commercial Real Estate (“CRE”) loans, the Company uses a grading system that relies on quantifiable and measurable characteristics when available. This includes comparison of financial strength to available industry averages, comparison of transaction factors (loan terms and conditions) to loan policy and comparison of credit history to stated repayment terms and industry averages. Some grading factors are necessarily more subjective such as economic and industry factors, regulatory environment and management. C&I and CRE loans are graded Doubtful, Substandard, Special Mention and Pass.

Doubtful- A Doubtful loan has a high probability of total or substantial loss, but because of specific pending events that may strengthen the asset, its classification as a loss is deferred. Doubtful borrowers are usually in default, lack adequate liquidity or capital and lack the resources necessary to remain an operating entity. Pending events can include mergers, acquisitions, liquidations, capital injections, the perfection of liens on additional collateral, the valuation of collateral and refinancing. Generally, pending events should be resolved within a relatively short period and the ratings will be adjusted based on the new information. Nonaccrual treatment is required for Doubtful assets because of the high probability of loss.

Substandard- Substandard loans have a high probability of payment default or they have other well-defined weaknesses. They require more intensive supervision by bank management. Substandard loans are generally characterized by current or expected unprofitable operations, inadequate debt service coverage, inadequate liquidity or marginal capitalization. Repayment may depend on collateral or other credit risk mitigants. For some Substandard loans, the likelihood of full collection of interest and principal may be in doubt and those loans should be placed on nonaccrual. Although Substandard assets in the aggregate will have a distinct potential for loss, an individual asset’s loss potential does not have to be distinct for the asset to be rated Substandard.

Special Mention - Special Mention loans have potential weaknesses that may, if not checked or corrected, weaken the asset or inadequately protect the Company’s position at some future date. These loans pose elevated risk, but their weakness does not yet justify a Substandard classification. Borrowers may be experiencing adverse operating trends (i.e., declining revenues or margins) or may be struggling with an ill-proportioned balance sheet (i.e., increasing inventory without an increase in sales, high leverage and/or tight liquidity). Adverse economic or market conditions, such as interest rate increases or the entry of a new competitor, may also support a Special Mention rating. Although a Special Mention loan has a higher PD than a Pass asset, its default is not imminent.

Pass - Loans graded as Pass encompass all loans not graded as Doubtful, Substandard or Special Mention. Pass loans are in compliance with loan covenants and payments are generally made as agreed. Pass loans range from superior quality to fair quality. Pass loans also include any portion of a government guaranteed loan.

Consumer and Residential Grading System

Consumer and Residential loans are graded as either Nonperforming or Performing.

Nonperforming- Nonperforming loans are loans that are (1) over 90 days past due and interest is still accruing or (2) on nonaccrual status.

Performing- All loans not meeting any of the above criteria are considered Performing.

The following tables illustrate the Company’s credit quality by loan class by vintage and includes gross charge-offs by loan class by vintage. Included in other consumer gross charge-offs for the nine months ended September 30, 2026, the Company recorded $0.4 million in overdrawn deposit accounts reported as 2025 originations and $0.6 million in overdrawn deposit accounts reported as 2026 originations. Included in other consumer gross charge-offs for the year ended December 31, 2025, the Company recorded $0.3 million in overdrawn deposit accounts reported as 2024 originations and $0.8 million in overdrawn deposit accounts reported as 2025 originations.

Allowance for Credit Losses on Off-Balance Sheet Credit Exposures

The allowance for credit losses on unfunded commitments totaled $6.0 million as of September 30, 2026, compared to $5.8 million as of December 31, 2025. The reserve for unfunded loan commitments was $0.5 million for the three months ended September 30, 2026, compared to $(0.3) million for the three months ended September 30, 2025. The reserve for unfunded loan commitments was $0.2 million for the nine months ended September 30, 2026, compared to $1.5 million for the nine months ended September 30, 2025. The reserve for unfunded loan commitments was recorded within other noninterest expense in the unaudited interim consolidated statements of income. Included in the reserve for unfunded loan commitments for the three and nine months ended September 30, 2025, was $0.5 million of acquisition-related provision for unfunded loan commitments due to the Evans acquisition.

Loan Modifications to Borrowers Experiencing Financial Difficulties

When the Company modifies a loan with financial difficulty, such modifications generally include one or a combination of the following: an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; a change in scheduled payment amount; or principal forgiveness.

The following tables show the amortized cost basis at the end of the reporting period of the loans modified to borrowers experiencing financial difficulty, disaggregated by class of financing receivable, type of concession granted and the financial effect of the modifications:

There wereno financing receivables that had a payment default during the three and nine months ended September 30, 2026, or during the three months ended September 30, 2025, that were modified to borrowers experiencing financial difficulty in the twelve months prior to the default. During the nine months ended September 30, 2025, there were $59 thousand of residential financing receivables with term extension modifications that had payment defaults during the period, that were modified to borrowers experiencing financial difficulty in the twelve months prior to the default.

The following tables depict the performance of loans that have been modified to borrowers experiencing financial difficulty that were modified in the prior twelve months:

8. Borrowings

Short-Term Borrowings

In addition to the liquidity provided by balance sheet cash flows, liquidity must also be supplemented with additional sources such as credit lines from correspondent banks as well as borrowings from the Federal Home Loan Bank (“FHLB”) and the Federal Reserve Bank. Other funding alternatives may also be appropriate from time to time, including wholesale and retail repurchase agreements and brokered certificate of deposit accounts.

Information related to short-term borrowings is summarized as follows:

See Note 5 for additional information regarding securities pledged as collateral for securities sold under the repurchase agreements.

Subordinated Debt

The subordinated notes assumed in connection with the Salisbury Bancorp, Inc. acquisition included $25.0 million of 3.50% fixed-to-floating rate subordinated notes due 2031. The subordinated notes, which qualified as Tier 2 capital, had a maturity date of March 31, 2031 and bore interest at an annual rate of 3.50%, payable quarterly in arrears commencing on June 30, 2021, and a floating rate of interest equivalent to thethree-month Secured Overnight Financing Rate (“SOFR”) plus a spread of 2.80%, payable quarterly in arrears commencing on June 30, 2026. The subordinated notes were redeemable, without penalty, on or after March 31, 2026. On June 30, 2026, the Company redeemed these subordinated notes in full using existing liquidity sources.

The following table summarizes the Company’s subordinated debt:

9. Defined Benefit Post-Retirement Plans

The Company has a qualified, noncontributory, defined benefit pension plan (the “Plan”) covering substantially all of its employees at September 30, 2026. Benefits paid from the Plan are based on age, years of service, compensation and social security benefits and are determined in accordance with defined formulas. The Company’s policy is to fund the Plan in accordance with Employee Retirement Income Security Act of 1974 standards. Assets of the Plan are invested in publicly traded stocks, bonds and mutual funds. In addition to the Plan, the Company provides supplemental employee retirement plans to certain current and former executives. These supplemental employee retirement plans and the Plan are collectively referred to herein as “Pension Benefits.”

In addition, the Company provides certain health care benefits for retired employees. Benefits were accrued over the employees’ active service period. Only employees that were employed by the Company on or before January 1, 2000 are eligible to receive post-retirement health care benefits. These post-retirement benefits are referred to herein as “Other Benefits.”

In connection with the Evans acquisition, the Company assumed the non-contributory, qualified, defined benefit pension plan and the nonqualified supplemental executive retirement plans. Effective May 2, 2025, the Evans defined benefit pension plan was merged into the Plan. The merging of the plans required a valuation as of the merger date and resulted in a $0.9 million adjustment to AOCI. The merging of the plans did not have a significant impact on the Company’s financial statements and related footnotes.

Accounting standards require an employer to: (1) recognize the overfunded or underfunded status of defined benefit post-retirement plans, which is measured as the difference between plan assets at fair value and the benefit obligation, as an asset or liability in its balance sheet; (2) recognize changes in that funded status in the year in which the changes occur through comprehensive income; and (3) measure the defined benefit plan assets and obligations as of the date of its year-end balance sheet.

The Company madeno voluntary contributions to the Pension Benefits and Other Benefits plans during the three and nine months ended September 30, 2026 and 2025.

The components of expense for Pension Benefits and Other Benefits are set forth below:

The service cost component of the net periodic (benefit) cost is included in salaries and employee benefits and the interest cost, expected return on plan assets and net amortization components are included in other noninterest expense on the unaudited interim consolidated statements of income.

10. Earnings Per Share

Basic earnings per share (“EPS”) excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity (such as the Company’s dilutive restricted stock units).

The following is a reconciliation of basic and diluted EPS for the periods presented in the unaudited interim consolidated statements of income:

There wereno shares of anti-dilutive restricted stock outstanding for the three and nine months ended September 30, 2026 and 2025.

11. Reclassification Adjustments Out of Other Comprehensive Income (Loss)

The following table summarizes the reclassification adjustments out of AOCI:

12. Derivative Instruments and Hedging Activities

The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate risk, primarily by managing the amount, sources and duration of its assets and liabilities and through the use of derivative instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which is determined by interest rates. Generally, the Company may use derivative financial instruments to manage differences in the amount, timing and duration of the Company’s known or expected cash receipts and its known or expected cash payments. Currently, the Company has interest rate derivatives resulting from a service provided to certain qualifying customers and, therefore, are not used to manage interest rate risk in the Company’s assets or liabilities. The Company manages a matched book with respect to its derivative instruments in order to minimize its net risk exposure resulting from such transactions.

Derivatives Not Designated as Hedging Instruments

The Company enters into interest rate swaps to facilitate customer transactions and meet their financing needs. These swaps are considered derivatives, but are not designated as hedging instruments. These instruments have interest rate and credit risk associated with them. To mitigate the interest rate risk, the Company enters into offsetting interest rate swaps with counterparties. The counterparty swaps are also considered derivatives and are also not designated as hedging instruments. Interest rate swaps are recorded within other assets or other liabilities on the consolidated balance sheets at their estimated fair value. Changes to the fair value of assets and liabilities arising from these derivatives are included, net, in other operating income in the consolidated statements of income.

The Company is subject to over-the-counter derivative clearing requirements, which require certain derivatives to be cleared through central clearing houses. Accordingly, the Company clears certain derivative transactions through the Chicago Mercantile Exchange Clearing House (“CME”). The CME requires the Company to post initial and variation margin payments to mitigate the risk of non-payment, the latter of which is received or paid daily based on the net asset or liability position of the contracts. A daily settlement occurs through the CME for changes in the fair value of centrally cleared derivatives. Not all of the derivatives are required to be cleared through the daily clearing agent. As a result, the total fair values of loan level derivative assets and liabilities recognized on the Company’s financial statements are not equal and offsetting.

As of September 30, 2026 and December 31, 2025, the Company hadtwenty-seven andtwenty-two risk participation agreements, respectively, with financial institution counterparties for interest rate swaps related to participated loans. Risk participation agreements provide credit protection to the financial institution that originated the swap transaction should the borrower fail to perform on its obligation. The Company enters into both risk participation agreements in which it purchases credit protection from other financial institutions and those in which it provides credit protection to other financial institutions.

The following table summarizes the derivatives outstanding:

(1)Netting adjustments represent the amounts recorded to convert derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance on the settle to market rules for cleared derivatives. The CME legally characterizes the variation margin posted between counterparties as settlements of the outstanding derivative contracts instead of cash collateral.

(2)Cash collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above.

The following table indicates the gain or loss recognized in income on derivatives not designated as hedging instruments:

13. Fair Value Measurements and Fair Value of Financial Instruments

GAAP states that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value measurements are not adjusted for transaction costs. A fair value hierarchy exists within GAAP that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:

Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices in markets that are not active or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability; and

Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.

The types of instruments valued based on quoted market prices in active markets include most U.S. government and agency securities, many other sovereign government obligations, liquid mortgage products, active listed equities and most money market securities. Such instruments are generally classified within Level 1 or Level 2 of the fair value hierarchy. The Company does not adjust the quoted prices for such instruments.

The types of instruments valued based on quoted prices in markets that are not active, broker or dealer quotations or quotes from alternative pricing sources with reasonable levels of price transparency include most investment-grade and high-yield corporate bonds, less liquid mortgage products, less liquid agency securities, less liquid listed equities, state, municipal and provincial obligations and certain physical commodities. Such instruments are generally classified within Level 2 of the fair value hierarchy. Certain common equity securities are reported at fair value utilizing Level 1 inputs (exchange quoted prices). Other investment securities are reported at fair value utilizing Level 1 and Level 2 inputs. The prices for Level 2 instruments are obtained through an independent pricing service or dealer market participants with whom the Company has historically transacted both purchases and sales of investment securities. Prices obtained from these sources include prices derived from market quotations and matrix pricing. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other factors. Management reviews the methodologies used by its third-party providers in pricing the securities.

Level 3 is for positions that are not traded in active markets or are subject to transfer restrictions. Valuations are adjusted to reflect illiquidity and/or non-transferability and such adjustments are generally based on available market evidence. In the absence of such evidence, management’s best estimate will be used. Management’s best estimate consists of both internal and external support on certain Level 3 investments. Subsequent to inception, management only changes Level 3 inputs and assumptions when corroborated by evidence such as transactions in similar instruments, completed or pending third-party transactions in the underlying investment or comparable entities, subsequent rounds of financing, recapitalizations and other transactions across the capital structure, offerings in the equity or debt markets and changes in financial ratios or cash flows.

The following tables set forth the Company’s financial assets and liabilities measured on a recurring basis that were accounted for at fair value. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement:

GAAP requires disclosure of assets and liabilities measured and recorded at fair value on a non-recurring basis such as goodwill, loans held for sale, other real estate owned, collateral-dependent loans individually evaluated for expected credit losses and HTM securities. As of September 30, 2026, the Company had collateral dependent individually evaluated loans with a carrying value of $34.0 million which were classified within Level 3 of the fair value hierarchy. Included in this amount were loans with fair value of $13.1 million where the amortized cost was adjusted to fair value. As of December 31, 2025, the Company had collateral dependent individually evaluated loans with a carrying value of $12.2 million which were classified within Level 3 of the fair value hierarchy. These loans with fair value of $12.2 million had their amortized cost adjusted to fair value. The Company uses the fair value of underlying collateral, less costs to sell, to estimate the allowance for credit losses for individually evaluated collateral dependent loans. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses ranging from 10% to 50%. Based on the valuation techniques used, the fair value measurements for collateral dependent individually evaluated loans are classified as Level 3.

The following table sets forth information with regard to estimated fair values of financial instruments. This table excludes financial instruments for which the carrying amount approximates fair value. Financial instruments for which the fair value approximates carrying value include cash and cash equivalents, AFS securities, equity securities, AIR, non-maturity deposits, short-term borrowings, accrued interest payable and derivatives.

Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Fair value estimates are based on existing on and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, the Company has a substantial wealth operation that contributes net fee income annually. The wealth management operation is not considered a financial instrument and its value has not been incorporated into the fair value estimates. Other significant assets and liabilities include the benefits resulting from the low-cost funding of deposit liabilities as compared to the cost of borrowing funds in the market and premises and equipment. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in the estimate of fair value.

*HTM Securities -*The fair value of the Company’s HTM securities is primarily measured using information from a third-party pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other factors.

*Net Loans -*Net loans include portfolio loans and loans held for sale. Loans were first segregated by type and then further segmented into fixed and variable rate and loan quality categories. Expected future cash flows were projected based on contractual cash flows, adjusted for estimated prepayments, and those expected future cash flows also includes credit risk, illiquidity risk and other market factors to calculate the exit price fair value in accordance with ASC 820.

*Time Deposits -*The fair value of time deposits was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. The fair values of the Company’s time deposit liabilities do not take into consideration the value of the Company’s long-term relationships with depositors, which may have significant value.

Long-Term Debt -The fair value of long-term debt was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments.

Subordinated Debt -The fair value of subordinated debt has been measured using the observable market price as of the period reported.

Junior Subordinated Debt -The fair value of junior subordinated debt has been estimated using a discounted cash flow analysis.

14. Commitments and Contingencies

The Company is a party to certain financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, unused lines of credit, standby letters of credit and certain agricultural real estate loans sold to investors with recourse, with the sold portion having a government guarantee that is assignable back to the Company upon repurchase of the loan in the event of default. The Company’s exposure to credit loss in the event of nonperformance by the other party to the commitments to extend credit, unused lines of credit, standby letters of credit and loans sold with recourse is represented by the contractual amount of those instruments. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness. Commitments to extend credit and unused lines of credit totaled $3.60 billion at September 30, 2026 and $3.40 billion at December 31, 2025.

Since many loan commitments, standby letters of credit and guarantees and indemnification contracts expire without being funded in whole or in part, the contract amounts are not necessarily indicative of future cash flows. The Company does not issue any guarantees that would require liability-recognition or disclosure, other than its standby letters of credit.

The Company guarantees the obligations or performance of customers by issuing standby letters of credit to third-parties. These standby letters of credit are generally issued in support of third-party debt, such as corporate debt issuances, industrial revenue bonds and municipal securities. The risk involved in issuing standby letters of credit is essentially the same as the credit risk involved in extending loan facilities to customers and letters of credit are subject to the same credit origination, portfolio maintenance and management procedures in effect to monitor other credit and off-balance sheet products. Typically, these instruments haveone year expirations with an option to renew upon annual review; therefore, the total amounts do not necessarily represent future cash requirements. Standby letters of credit totaled $68.5 million at September 30, 2026 and $58.5 million at December 31, 2025. As of September 30, 2026 and December 31, 2025, the fair value of the Company’s standby letters of credit was not significant.

In the normal course of business there are various outstanding legal proceedings. The Company accrues for material estimated losses from loss contingencies if the information available indicates that it is probable that a liability had been incurred at the date of the financial statements and the amount of loss can be reasonably estimated.

15. Segment Reporting

Management assesses its operating segment structure to enhance transparency in how financial performance is evaluated and resources are allocated by the chief operating decision maker (“CODM”). Segments are components of an enterprise that are regularly evaluated by the CODM to allocate resources and assess performance. The Company’s CODM is its Chief Executive Officer.

The Company has determined that it operates throughtwo reportable segments:

Banking– Provides commercial banking, retail banking, and wealth management services primarily to customers in its market area, offering a broad array of banking and financial services to retail, commercial, and municipal customers. Included in Banking are the revenue and expenses from the wealth management business and the parent holding company. The parent company’s principal activities include the direct and indirect ownership of banking and non-banking subsidiaries, as well as the issuance of debt and equity. The parent company’s principal sources of revenue are the management fees and dividends it receives from its subsidiaries. Banking also includes corporate shared service costs such as the majority of equity compensation expense, as well as other general and administrative shared services costs including pension, retirement plan and supplemental retirement plan costs. Currently there is no allocation of these costs to other operating segments.

Retirement Plan Administration – Includes retirement plan and health savings account recordkeeping and administration, investment management, third-party administration, and actuarial services.

Our CODM reviews actual net income versus budgeted net income to assess segment performance and to make decisions about allocating capital and personnel to the segments. The CODM regularly receives expense information at a level consistent with that disclosed in the Company’s consolidated statements of income.

Reported segments and their financial information are not necessarily comparable to similar information reported by other financial institutions. Additionally, due to interrelationships among the various segments, the information presented is not indicative of how the segments would perform as independent entities. Changes in management structure, allocation methodologies, or procedures may result in future revisions to previously reported segment financial data. There have been no changes to the Company’s operating segments since those disclosed in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025. The Company will continue to evaluate its segment disclosures and make necessary adjustments as business operations evolve.

Information about reportable segments and reconciliation of the information to the consolidated financial statements follows:

(1)Included in All Other is the revenue and expenses from certain other non-bank subsidiaries of the parent, including the insurance subsidiary, along with eliminating amounts that do not meet the definition of an operating segment.

(1) Included in All Other is the revenue and expenses from certain other non-bank subsidiaries of the parent, including the insurance subsidiary, along with eliminating amounts that do not meet the definition of an operating segment.

(1) Included in All Other is the revenue and expenses from certain other non-bank subsidiaries of the parent, including the insurance subsidiary, along with eliminating amounts that do not meet the definition of an operating segment.

(1) Included in All Other is the revenue and expenses from certain other non-bank subsidiaries of the parent, including the insurance subsidiary, along with eliminating amounts that do not meet the definition of an operating segment.

NBT BANCORP INC. AND SUBSIDIARIES