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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

QUARTERLY PERIOD ENDED September 30, 2013

Commission File Number 1-34073

Huntington Bancshares Incorporated

41 South High Street, Columbus, Ohio 43287

Registrant’s telephone number (614) 480-8300

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    x  Yes    ¨  No

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    x  Yes    ¨  No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).     ¨  Yes    x  No

There were 830,517,677 shares of Registrant’s common stock ($0.01 par value) outstanding on October 31, 2013.

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HUNTINGTON BANCSHARES INCORPORATED

INDEX

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Glossary of Acronyms and Terms

The following listing provides a comprehensive reference of common acronyms and terms used throughout the document:

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PART I. FINANCIAL INFORMATION

When we refer to “we,” “our,” and “us” in this report, we mean Huntington Bancshares Incorporated and our consolidated subsidiaries, unless the context indicates that we refer only to the parent company, Huntington Bancshares Incorporated. When we refer to the “Bank” in this report, we mean our only bank subsidiary, The Huntington National Bank, and its subsidiaries.

INTRODUCTION

We are a multi-state diversified regional bank holding company organized under Maryland law in 1966 and headquartered in Columbus, Ohio. Through the Bank, we have 147 years of serving the financial needs of our customers. Through our subsidiaries, we provide full-service commercial and consumer banking services, mortgage banking services, automobile financing, equipment leasing, investment management, trust services, brokerage services, customized insurance service programs, and other financial products and services. Our over 700 banking offices are located in Indiana, Kentucky, Michigan, Ohio, Pennsylvania, and West Virginia. Selected financial services and other activities are also conducted in various other states. International banking services are available through the headquarters office in Columbus, Ohio and a limited purpose office located in the Cayman Islands and another limited purpose office located in Hong Kong. Our foreign banking activities, in total or with any individual country, are not significant.

This MD&A provides information we believe necessary for understanding our financial condition, changes in financial condition, results of operations, and cash flows. The MD&A included in our 2012 Form 10-K should be read in conjunction with this MD&A as this discussion provides only material updates to the 2012 Form 10-K. This MD&A should also be read in conjunction with the financial statements, notes and other information contained in this report.

Our discussion is divided into key segments:

A reading of each section is important to understand fully the nature of our financial performance and prospects.

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EXECUTIVE OVERVIEW

Summary of 2013 Third Quarter Results

For the quarter, we reported net income of $178.5 million, or $0.20 per common share, compared with $150.7 million, or $0.17 per common share, in the prior quarter (see Table 1).

Fully-taxable equivalent net interest income was $431.5 million for the quarter, unchanged from the prior quarter. The results reflected a $0.1 billion increase in average earning assets, as well as an additional day in the quarter. These were offset by a 4 basis point decrease in the net interest margin. The primary items affecting the net interest margin were a 4 basis point negative impact from the mix and yield of earning assets, a 3 basis point negative impact of the $750 million of debt issued during the quarter, and a 3 basis point positive impact from lower cost of deposits.

The provision for credit losses decreased $13.3 million, or 54%, from the prior quarter. This quarter, we introduced an enhanced allowance methodology, which incorporates an enhanced commercial risk rating system. The combination of the enhanced methodology and continued improvement in overall asset quality resulted in a reduction in the ACL to loans ratio of 1.72%, compared to 1.86% in the prior quarter. The ACL as a percentage of period-end NALs increased 6 percentage points to 220%. NALs declined by $30.4 million, or 8%, to $333.1 million, or 0.78% of total loans. The decreases primarily reflected meaningful improvement in both C&I and CRE NALs.

Noninterest income increased $1.8 million, or 1%, from the prior quarter. The increase reflected the $8.0 million, or 31%, increase in other noninterest income, primarily related to fees associated with commercial loan activity, and the $4.9 million, or 7%, increase in service charges on deposit accounts, resulting from household and commercial relationship growth. These were offset by a $10.0 million, or 30%, decrease in mortgage banking income due to lower origination volume, and the $3.0 million, or 15%, decrease in brokerage income due to typical seasonal trends.

Noninterest expense decreased $22.5 million, or 5%, from the prior quarter. The decrease reflected the $34.5 million, or 13%, decrease in personnel costs, which included a significant item of $33.9 million from the pension curtailment gain and $6.6 million of branch consolidation and severance expense. These were partially offset by a $7.9 million, or 29%, increase in net occupancy, and a $3.2 million, or 13%, increase in equipment, which combined included a significant item of $9.5 million for branch consolidation and facilities optimization related costs. In addition, outside services included a significant item of $0.5 million for branch consolidation and facilities optimization related costs.

The tangible common equity to tangible asset ratio increased to 9.02% from 8.78% at the end of the prior quarter, resulting primarily from earnings retention. Our Tier 1 common risk-based capital ratio at quarter end was 10.85%, up from 10.71% at the end of the prior quarter. The regulatory Tier 1 risk-based capital ratio at September 30, 2013 was 12.36%, up from 12.24% at June 30, 2013. All capital ratios were impacted by the repurchase of 2.0 million common shares over the quarter at an average price per share of $8.18.

Business Overview

General

Our general business objectives are: (1) grow net interest income and fee income, (2) increase cross-sell and share-of-wallet across all business segments, (3) improve efficiency ratio, (4) continue to strengthen risk management, including sustained improvement in credit metrics, and (5) maintain strong capital and liquidity positions.

Our third-quarter results demonstrated that our unique products and services are driving robust organic customer acquisition across our commercial and consumer customer base, while delivering stable returns to shareholders. Through our disciplined investments in fee-income businesses in conjunction with prudent expense management, we have been able to deliver modest positive operating leverage for the first nine months of the year.

During the quarter, we successfully launched our consumer credit card product. The third quarter was also a time of continuing household growth, particularly within our in-store branches, and marked a return to stability for our commercial real estate loan portfolio. Our performance benefited from ongoing improvement within our core Midwestern economies. We also made progress in managing expenses, including one-time savings attributable to pension curtailment, rightsizing of some investments, and the consolidation of 22 branch locations.

Economy

While we are optimistic about continuing indicators of economic improvement supporting our performance for the next several quarters, we must face the headwinds related to the yield curve, regulatory environment, and ongoing uncertainty in Washington.

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Legislative and Regulatory

Regulatory reforms continue to be issued, which impose additional restrictions on current business practices. Recent items affecting us include the Federal Reserve’s Capital Plan Review and the recently issued final Basel III capital rule.

Capital Plans Rule / Supervisory and Company-Run Stress Test Requirements – The Federal Reserve issued two interim final rules on September 24, 2013, that are intended to clarify how we should incorporate the Basel III regulatory capital reforms into our capital projections during the next cycle of capital plan submissions and stress tests. The planning horizon for the next capital planning and stress testing cycle encompasses the 2013 fourth quarter through the 2015 fourth quarter. Rules to implement the Basel III capital reforms in the United States were finalized in July 2013, and will be phased-in beginning in 2015 for us under the standardized approach. As such, the next CCAR cycle, which began October 1, 2013, overlaps with the implementation of the Basel III capital reforms based on the required 9-quarter capital projections. The interim final rules clarify that banking organizations with $50 billion or more in total consolidated assets, including us, must incorporate the revised capital framework into the capital planning projections and into the stress tests required under the Dodd-Frank Act using the transition paths established in the Basel III final rule. The rule also clarifies that for the upcoming cycle, capital adequacy at large banking organizations, including us, would continue to be assessed against a minimum 5 percent tier 1 common ratio calculated in the same manner as under previous stress tests and capital plan submissions, ensuring consistency with those previous exercises. The interim final rules became effective upon issuance, but the Federal Reserve will accept comments on the rules through November 25, 2013.

Basel III Capital rules for U.S. banking organizations – On July 2, 2013, the Federal Reserve voted to adopt final Basel III capital rules for U.S. Banking organizations. The final rules establish an integrated regulatory capital framework and will implement in the United States the Basel III regulatory capital reforms from the Basel Committee on Banking Supervision and certain changes required by the Dodd-Frank Act. Under the final rule, minimum requirements will increase for both the quantity and quality of capital held by banking organizations. Consistent with the international Basel framework, the final rule includes a new minimum ratio of common equity tier 1 capital (Tier I Common) to risk-weighted assets and a Tier 1 Common capital conservation buffer of 2.5% of risk-weighted assets that will apply to all supervised financial institutions. The rule also raises the minimum ratio of tier 1 capital to risk-weighted assets and includes a minimum leverage ratio of 4% for all banking organizations. These new minimum capital ratios will become effective for us on January 1, 2015, and will be fully phased-in on January 1, 2019.

Following are the Basel III regulatory capital levels that we must satisfy to avoid limitations on capital distributions and discretionary bonus payments during the applicable transition period, from January 1, 2015 until January 1, 2019:

The final rule emphasizes Tier 1 Common capital, the most loss-absorbing form of capital, and implements strict eligibility criteria for regulatory capital instruments. The final rule also improves the methodology for calculating risk-weighted assets to enhance risk sensitivity. Banks and regulators use risk weighting to assign different levels of risk to different classes of assets.

We have evaluated the impact of the Basel III final rule on our regulatory capital ratios and estimate a reduction of approximately 60 basis points to our Basel I Tier I Common risk-based capital ratio based on our June 30, 2013 balance sheet composition. The estimate is based on management’s current interpretation, expectations, and understanding of the final U.S. Basel III rules. We anticipate that our capital ratios, on a Basel III basis, will continue to exceed the well capitalized minimum capital requirements. We are evaluating options to mitigate the capital impact of the final rule prior to its effective implementation date.

Approximately $50.0 million of our Tier 1 risk-based capital of $6.0 billion at September 30, 2013 consisted of the outstanding Class C preferred securities of our REIT subsidiary, Huntington Preferred Capital, Inc. (HPCI). Based on our review of the Basel III final rule, it is likely that when Basel III becomes effective, the HPCI Class C preferred securities will no longer constitute Tier 1 capital for us or the Bank. In the event we determine that a “regulatory capital event” has occurred, based on an opinion of counsel rendered by a law firm experienced in such matters, HPCI would have the right to redeem the outstanding Class C preferred securities. In the event HPCI redeems the Class C preferred securities, holders of such securities will be entitled to receive the redemption price of $25.00 per share plus accrued and unpaid dividends on such shares. The redemption price may differ from the redemption date market price of the Class C preferred securities. There can be no assurance as to if or when HPCI would redeem the Class C preferred securities.

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Expectations

Net interest income is expected to modestly grow over the next several quarters. We anticipate an increase in earning assets as total loans modestly grow and investment securities increase in preparation for the new liquidity rules. However, those benefits to net interest income are expected to be partially offset by continued modest downward pressure on NIM until the short end of the yield curve begins to move higher. Full-year 2013 NIM is not expected to fall below the mid 3.30%’s. While we are maintaining a disciplined approach to loan pricing, asset yields remain under pressure, and that is partially offset by the continued deposit repricing and mix shift.

The C&I portfolio is expected to see growth consistent with an anticipated increase in customer activity. Our C&I loan pipeline remains robust with much of this reflecting the positive impact from our investments in specialized commercial verticals, focused OCR sales process, and continued support of middle market and small business lending. Automobile loan originations remain strong, and we currently do not anticipate any automobile securitizations in the near future. Residential mortgages, home equity, and CRE loan balances are expected to increase modestly.

We anticipate the increase in total loans will outpace growth in total deposits. This reflects our continued focus on the overall cost of funds, as well as the continued shift towards low- and no-cost demand deposits and money market deposit accounts.

Noninterest income, when compared to recent levels, is expected to be relatively flat, excluding the impact of any automobile loan sales, any net MSR activity, and typical first quarter seasonality.

Expenses, excluding the $17 million of Significant Items, are expected to modestly increase due to higher depreciation, personnel, occupancy, and equipment expense related to our continued modest pace of investments. We continue to evaluate additional cost saving opportunities, and an additional $6 million of branch consolidation expense is expected in the 2013 fourth quarter from previously announced actions. We remain committed to posting positive operating leverage for the 2013 full year.

NPAs are expected to show continued improvement. This quarter, NCOs were at the high end of our expected normalized range of 35 to 55 basis points. The level of provision for credit losses was below our long-term expectation, and we continue to expect some quarterly volatility.

The effective tax rate for 2013 is expected to be in the range of 25% to 27%, primarily reflecting the impacts of tax-exempt income, tax-advantaged investments, and general business credits.

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DISCUSSION OF RESULTS OF OPERATIONS

This section provides a review of financial performance from a consolidated perspective. It also includes a “Significant Items” section that summarizes key issues important for a complete understanding of performance trends. Key Unaudited Condensed Consolidated Balance Sheet and Unaudited Condensed Statement of Income trends are discussed. All earnings per share data are reported on a diluted basis. For additional insight on financial performance, please read this section in conjunction with the “Business Segment Discussion.”

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Table 1—Selected Quarterly Income Statement Data (1)

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Table 2—Selected Year to Date Income Statement Data(1)

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Significant Items

Definition of Significant Items

From time-to-time, revenue, expenses, or taxes are impacted by items judged by us to be outside of ordinary banking activities and / or by items that, while they may be associated with ordinary banking activities, are so unusually large that their outsized impact is believed by us at that time to be infrequent or short-term in nature. We refer to such items as Significant Items. Most often, these Significant Items result from factors originating outside the company; e.g., regulatory actions / assessments, windfall gains, changes in accounting principles, one-time tax assessments / refunds, litigation actions, etc. In other cases, they may result from our decisions associated with significant corporate actions outside of the ordinary course of business; e.g., merger / restructuring charges, recapitalization actions, goodwill impairment, etc.

Even though certain revenue and expense items are naturally subject to more volatility than others due to changes in market and economic environment conditions, as a general rule volatility alone does not define a Significant Item. For example, changes in the provision for credit losses, gains / losses from investment activities, asset valuation writedowns, etc., reflect ordinary banking activities and are, therefore, typically excluded from consideration as a Significant Item.

We believe the disclosure of Significant Items provides a better understanding of our performance and trends to ascertain which of such items, if any, to include or exclude from an analysis of our performance; i.e., within the context of determining how that performance differed from expectations, as well as how, if at all, to adjust estimates of future performance accordingly. To this end, we adopted a practice of listing Significant Items in our external disclosure documents; e.g., earnings press releases, investor presentations, Forms 10-Q and 10-K.

Significant Items for any particular period are not intended to be a complete list of items that may materially impact current or future period performance.

Significant Items Influencing Financial Performance Comparisons

Earnings comparisons were impacted by the Significant Items summarized below:

The following table reflects the earnings impact of the above-mentioned Significant Items for periods affected by this Results of Operations discussion:

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Table 3—Significant Items Influencing Earnings Performance Comparison (1)