SUBJECT TO COMPLETION

SUBJECT TO COMPLETION vi d PRELIMINARY PROSPECTUS SUPPLEMENT DATED OCTOBER I.2015 eu PROSPECTUS SUPPLEMENT ^.= .— (To Prospectus dated March 2. 2015) ria cn = H O o alt" SOUTHERNVs a = COMPANY c▪ a G3 = V7 Series 2015A % Junior Subordinated Notes G3 a ! en 7.5 due October 15, 2075 = = O te• a` E lad .= EFtc • c 0. 0 a) O 0 0. ▪ r, Jr.v, zo 4,?= t Tot •a• a) G, /3) E 0 = CD cal 0.6 O. 0 CD ^ya) a)NL • = 3 Tue_ o.. Initial public offering price (I) = o P "t3 ▪ it 12 mien% riting discount (2) co .02 a a. Proceeds. he expenses. to the Southern Company (2) ra '= E = y,_ • V) CO viz._ E O 0=• co 0.0 ca and ▪ C E 2 .2 I= a. CT, •••• >.. 0 = 03 Ee m9 0 o. co = u) .—s The Series 20I5A °/• Junior Subordinated Notes due October 15.2075 will bear interest at a fixed raw of %per year. Interest will be payable quarterly in arrears on January IS. April 15. July 15 and October IS of each year. beginning on January I5.2016. The Series 2015A Junior Subordinated Notes will be issued in registered form and in denominations of $25.00 and integral multiples of $25.00 in excess thereof. The Series 2015A Junior Subordinated Notes will mature on October I5.2075. So long as no Event of Default has occurred and is continuing. The Southern Company may defer interest payments on the Series 2015A Junior Subordinated Notes on one or more occasions for up to 40 consecutive quarterly periods as described in this Prospectus Supplement. Deferred interest payments will accrue additional interest at a rate equal to the interest rate then applicable to the Series 2015A Junior Subordinated Notes. compounded quarterly. to the extent permitted by applicable law. The Southern Company may redeem the Series 2015A Junior Subordinated Notes at its option at the times and the prices described in this Prospectus Supplement. The Series 20I5A Junior Subordinated Notes are a new issue of securities with no established trading market. The Southern Company intends to apply to list the Series 2015A Junior Subordinated Notes on the New York Stock Exchange. If the application is approved. The Southern Company expects trading in the Series 2015A Junior Subordinated Notes to begin within 30 days after the date that the Series 2015A Junior Subordinated Notes arc first issued. See "RISK FACTORS- beginning on page S-8 for a description ofcertain risks associated with investing in the Series 20154 Junior Subordinated Notes. • E ru no CL CA ••IA BofA Merrill Lynch Morgan Stanley UBS Investment Bank Wells Fargo Securities o 0 r, 0_ c = ' t• t-Senior Co-Mantle(•r. ▪ s E XBarclays Citigroup J.P. Morgan ▪-0 0_▪ -0 r-= 2 §— := co os October , 2015 Per Series 20I5A Junior Subordinated Note Ye Ye Total $ (I) Plus accrued interest. if any. from the date of original issuance of the Series 2015AJunio Subordinated Notes. which is expected to be October 2015. (2) An underwriting discount of S per Series 20I5A Junior Subordinated Note (or up to $ for all Series 20I5A Junior Subordinated Notes) will be deducted from the proceeds paid to The Southern Company by the underwriters. However, the discount will be $ per Series 20I5A Junior Subordinated Note for sales to institutions and, to the extent of such institutional sales. the total underwriting discount will be less than the amount set forth in the above table. As a result of sales to institutions, the total proceeds to The Southern Company increased by $ . Certain other expenses of the offering will be paid by The Southern Company. Sec -Undenvriting. - Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this Prospectus Supplement or the accompanying Prospectus. Any representation to the contrary is a criminal offense. The underwriters will have the option to purchase up to an additional $ in principal amount of the Series 2015A Junior Subordinated Notes in order to cover over-allotments. if any. lithe option is exercised, any such Series 20I5A Junior Subordinated Notes arc expected to be delivered on or about the same date set forth in the paragraph below. Should the underwriters exercise this option in full, the total initial public offering price. underwriting discount and proceeds. before expenses. to The Southern Company will be $ . S and $ . respectively. The Series 2015A Junior Subordinated Notes are expected to be delivered on or about October , 2015 through the book-entry facilities of The Depository Trust Company. Joint Book-Running Managers EFTA01121419 No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this Prospectus Supplement, the accompanying Prospectus or any written communication from The Southern Company or the underwriters specifying the final terms of the offering. Neither The Southern Company nor any underwriter takes any responsibility for, nor can it provide any assurance as to the reliability of, any other information that others may give you. This Prospectus Supplement, the accompanying Prospectus and any written communication from The Southern Company or the underwriters specifying the final terms of the offering is an offer to sell only the Series 2015A Junior Subordinated Notes offered hereby, and only under circumstances and in jurisdictions where it is lawful to do so. The information incorporated by reference or contained in this Prospectus Supplement, the accompanying Prospectus and any written communication from The Southern Company or the underwriters specifying the final terms of the offering is current only as of its respective date. TABLE OF CONTENTS Page Prospectus Supplement Summary S-3 Risk Factors S-8 Selected Financial Information S-9 Use of Proceeds 5.10 Description of the Series 2015A Junior Subordinated Notes 5.10 Material United States Federal Income Tax Considerations S- I 5 Underwriting (Conflicts of Interest) 5.21 Prospectus About this Prospectus Risk Factors Available Information. Incorporation of Certain Documents by Reference The Southern Company 2 Certain Ratios 2 Use of Proceeds 2 Description of the Common Stock 3 Description of the Senior Notes 3 Description of the Junior Subordinated Notes 6 Plan of Distribution I I Legal Matters II Experts II S-2 EFTA01121420 SUMMARY The following summary is qualified in its entirety by, and should be read together with, the more detailed information that is included elsewhere in this Prospectus Supplement and the accompanying Prospectus, as well as the information that is incorporated or deemed to be incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. Investing in the Series 2015A Junior Subordinated Notes involves risks. See "Risk Factors" beginning on page S-8 in this Prospectus Supplement. The Southern Company The Southern Company (the "Company") was incorporated under the laws of Delaware on November 9, 1945. The Company is domesticated under the laws of Georgia and is qualified to do business as a foreign corporation under the laws of Alabama. The principal executive offices of the Company are located at 30 Ivan Allen Jr. Boulevard, N.W., Atlanta, Georgia 30308, and the telephone number is (404) 506-5000. The Offering Issuer Security Offered Maturity Interest Rate Interest Payment Dates Option to Deter Interest Payments The Southern Company. The Company is offering $ aggregate principal amount ($ aggregate principal amount if the underwriters exercise their over-allotment option in full) of its Series 20I5A % Junior Subordinated Notes due October 15, 2075. The Series 2015A Junior Subordinated Notes will be issued in registered form and in denominations of $25.00 and integral multiples of $25.00 in excess thereof. The Series 2015A Junior Subordinated Notes will mature on October 15, 2075. The Series 20I5A Junior Subordinated Notes will bear interest at a fixed rate of % per year. Subject to the Company's right to defer interest payments as described below, interest on the Series 20I5A Junior Subordinated Notes will be payable quarterly in arrears on January 15, April I5, July 15 and October 15 of each year (each, an "Interest Payment Date"), beginning on January I5, 2016. So long as no Event of Default (as defined herein) has occurred and is continuing, at the Company's option, it may, on one or more occasions, defer payment of all or part of the current and accrued interest otherwise due on the Series 2015A Junior Subordinated Notes by extending the interest payment period for up to 40 consecutive quarterly periods (each period, commencing on the date that the first such interest payment would othenvise have been made, an "Optional Deferral Period"). In other words, the Company may declare at its discretion up to a 10-year interest payment moratorium on the Series 20I5A Junior Subordinated Notes and may choose to do so on more than one occasion. A deferral of interest payments may not extend beyond the maturity date of the Series 2015A Junior Subordinated Notes or end on a day other than an Interest Payment Date. Any deferred interest on the Series 20I5A Junior Subordinated Notes will accrue additional interest at a rate of % per year, compounded quarterly, to the extent permitted under applicable law. Once the Company pays all deferred interest payments on the Series 20I5A Junior Subordinated Notes, including any additional interest accrued on the deferred interest, it can again defer interest payments on the Series 20I5A Junior Subordinated Notes as described above, but not beyond the maturity date of the Series 20I5A Junior Subordinated Notes. S-3 EFTA01121421 The Company is required to provide to the Subordinated Note Indenture Trustee (as defined herein) written notice of any optional deferral of interest at least 10 and not more than 60 Business Days prior to the earlier of (I) the next applicable Interest Payment Date or (2) the date, if any, upon which the Company is required to give notice of such Interest Payment Date or the record date therefor to the New York Stock Exchange or any applicable self-regulatory organization. The Subordinated Note Indenture Trustee is required to promptly forward any such notice to each holder of record of the Series 2015A Junior Subordinated Notes. If the Company elects to defer interest on the Series 20I5A Junior Subordinated Notes for one or more Optional Deferral Periods, the beneficial owners of the Series 2015A Junior Subordinated Notes will be required to accrue income for United States federal income tax purposes in the amount of the accrued and unpaid interest payments on the Series 2015A Junior Subordinated Notes, in the form of original issue discount, even though cash interest payments are deferred and even though the beneficial owners may be cash-basis taxpayers. Certain Restrictions during Optional Deferral Period During an Optional Deferral Period, the Company will not be permitted to do any of the following, with certain limited exceptions described below under "Description of the Series 2015A Junior Subordinated Notes—Certain Limitations During an Optional Deferral Period": • declare or pay any dividend or make any distributions with respect to, or redeem, purchase, acquire or make a liquidation payment with respect to, any of the capital stock of the Company; or make any payment of interest on, principal of or premium, if any, on or repay, repurchase or redeem any of the Company's debt securities (including guarantees) that rank equally with or junior in right of payment to the Series 2015A Junior Subordinated Notes. Optional Redemption The Company may redeem the Series 2015A Junior Subordinated Notes at its option before their maturity: • in whole or in part, on one or more occasions, on or after October 15, 2020 at 100% of their principal amount, plus any accrued and unpaid interest thereon; • in whole, but not in part, before October 15, 2020 at 100% of their principal amount, plus any accrued and unpaid interest thereon, if certain changes in tax laws, regulations or interpretations occur, or in whole, but not in part, before October 15, 2020 at 102% of their principal amount, plus any accrued and unpaid interest thereon, if a rating agency makes certain changes in the equity credit criteria for securities such as the Series 2015A Junior Subordinated Notes. For a more complete description of the circumstances under and the redemption prices at which the Series 2015A Junior Subordinated Notes may be redeemed, see "Description of the Series 20I5A Junior Subordinated Notes—Optional Redemption," "Description of the Series 20I5A Junior Subordinated Notes—Right to Redeem Upon a Tax Event" and "Description of the Series 2015A Junior Subordinated Notes—Right to Redeem Upon a Rating Agency Event" in this Prospectus Supplement. S-4 EFTA01121422 Subordination; Ranking The Company's obligations under the Series 2015A Junior Subordinated Notes are unsecured and rank junior in right of payment to all of the Company's "Senior Indebtedness," whether presently existing or from time to time hereafter incurred, created, assumed or existing, as defined below under "Description of the Junior Subordinated Notes—Subordination" in the accompanying Prospectus. As of June 30, 2015, the Senior Indebtedness of the Company, on an unconsolidated basis, aggregated approximately $2.9 billion. Since the Company is a holding company, its right and, hence, the right of its creditors (including holders of the Series 2015A Junior Subordinated Notes) to participate in any distribution of the assets of any subsidiary of the Company, whether upon liquidation, reorganization or otherwise, is structurally subordinated to claims of creditors and preferred and preference stockholders of each subsidiary. As of June 30, 2015, on a consolidated basis, the Company had approximately $26.3 billion of outstanding long-term debt (including securities due within one year), of which approximately $23.6 billion was long-term debt (including securities due within one year) of the Company's subsidiaries. In addition, the Company had approximately $1.1 billion of short-term notes payable, of which approximately $0.9 billion was short-term notes payable of the Company's subsidiaries. In addition, as of June 30, 2015, the Company's subsidiaries had approximately $0.7 billion of preferred and preference stock outstanding. There are no terms of the Series 2015A Junior Subordinated Notes that limit the Company's ability to incur additional Senior Indebtedness, or that limit its subsidiaries' ability to incur additional debt or other liabilities or issue preferred and preference stock. Events of Default The following are the Events of Default with respect to the Series 20I5A Junior Subordinated Notes: Listing • failure to pay principal of, or premium, if any, on or interest on the Series 20I5A Junior Subordinated Notes when due at maturity or earlier redemption; failure to pay interest on the Series 20I5A Junior Subordinated Notes when due and payable (other than at maturity or upon earlier redemption) that continues for 30 days (subject to the Company's right to optionally defer interest payments); or • certain events of bankruptcy, insolvency or reorganization involving the Company. The Company intends to apply to list the Series 2015A Junior Subordinated Notes on the New York Stock Exchange. If the application is approved, the Company expects trading in the Series 20I5A Junior Subordinated Notes to begin within 30 days after the date that the Series 2015A Junior Subordinated Notes are first issued. No Sinking Fund The Series 20I5A Junior Subordinated Notes do not have the benefit of a sinking fund. Use of Proceeds The net proceeds from the sale of the Series 2015A Junior Subordinated Notes will be used by the Company to pay a portion of its outstanding short-term indebtedness, which aggregated approximately $524,000,000 as of September 30, 2015, and for other general corporate purposes, including investment by the Company in its subsidiaries. S-5 EFTA01121423 Conflicts of Interest Book-Entry Further Issues Certain of the underwriters or their affiliates hold a portion of the short-term indebtedness that the Company intends to repay using a portion of the net proceeds from the sale of the Series 2015A Junior Subordinated Notes. It is possible that one or more of the underwriters or their affiliates could receive 5% or more of the net proceeds from the sale of the Series 2015A Junior Subordinated Notes, and, in that case, such underwriter would be deemed to have a "conflict of interest" within the meaning of Financial Industry Regulatory Authority ("FINRA") Rule 5121. In the event of any such conflict of interest, such underwriter would be required to conduct the distribution of the Series 2015A Junior Subordinated Notes in accordance with FINRA Rule 5121. If the distribution is conducted in accordance with FINRA Rule 5121, such underwriter would not be permitted to confirm a sale of a Series 2015A Junior Subordinated Note in this offering to an account over which it exercises discretionary authority without the prior specific written approval of the account holder. The Series 2015A Junior Subordinated Notes will be represented by one or more global securities that will be deposited with a custodian for and registered in the name of The Depository Trust Company, New York, New York ("DTC") or its nominee. This means that investors will not receive a certificate for their Series 2015A Junior Subordinated Notes but, instead, will hold their interest through DTC's system. The Company may, without the consent of the holders, issue additional junior subordinated notes that will constitute one series and be fungible with the Series 2015A Junior Subordinated Notes. Governing Law New York. Risk Factors An investment in the Series 2015A Junior Subordinated Notes involves risks. A prospective investor should carefully consider the discussion of risks in "Risk Factors" in this Prospectus Supplement and the other information in this Prospectus Supplement and the accompanying Prospectus, before deciding whether an investment in the Series 2015A Junior Subordinated Notes is suitable for such investor. Recent Developments Agreement to Acquire AGL Resources, Inc. On August 23, 2015, the Company, AGL Resources Inc., a Georgia corporation ("AGL Resources"), and AMS Corp., a Georgia corporation ("Merger Sub"), entered into an Agreement and Plan of Merger (the "Merger Agreement") providing for the merger of Merger Sub with and into AGL Resources on the terms and subject to the conditions set forth in the Merger Agreement (the "Merger"), with AGL Resources continuing as the surviving corporation and a wholly-owned, direct subsidiary of the Company. The Merger Agreement provides that at the effective time of the Merger (the "Effective Time"), each share of common stock of AGL Resources issued and outstanding immediately prior to the Effective lime (other than dissenting shares) will be cancelled and convened into the right to receive $66 in cash, without interest. The completion of the Merger is subject to the satisfaction or waiver of certain closing conditions, including, among others, (i) approval of the Merger Agreement by AGL Resources' shareholders, (ii) the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act, (iii) the receipt of all required regulatory approvals from certain governmental entities, including, among others, the Federal Communications Commission and certain state utilities and other regulatory commissions, and (iv) other closing conditions. S-6 EFTA01121424 In connection with the Merger Agreement, on August 23, 2015, the Company entered into a Commitment Letter (the "Commitment Letter") with Citigroup Global Markets, Inc. ("Citigroup") pursuant to which Citigroup has committed to provide debt financing for the transaction, consisting of an $8.1 billion senior unsecured bridge facility (the "Bridge Facility") (minus the net cash proceeds from certain securities issuances by the Company and other specified amounts as provided therein). The Commitment Letter provides that the obligation of Citigroup to provide this debt financing is subject to a number of conditions, including, without limitation, execution and delivery of certain definitive documentation. On September 30, 2015, the Company entered into a Bridge Credit Agreement with Citigroup and certain other lenders, which serves as the definitive documentation for the Bridge Facility. S-7 EFTA01121425 RISK FACTORS Investing in the Series 2015A Junior Subordinated Notes involves risk. In addition to the factors described below, please see the risk factors in the Annual Report on Form 10-K of the Company for the fiscal year ended December 31, 2014 (the "Form 10-K"), along with disclosure related to the risk factors contained in the Company's Quarterly Reports on Form 10-Q for the quarters ended March 31, 2015 and June 30, 2015, which are incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. Before making an investment decision, you should carefully consider these risks as well as other information contained or incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The risks and uncertainties not presently known to the Company or that the Company currently deems immaterial may also impair its business operations, its financial results and the value of the Series 2015A Junior Subordinated Notes. The Series 20I5A Junior Subordinated Notes are effectively subordinated to substantially all of the Company's other debt, and the indenture governing the Series 20I5A Junior Subordinated Notes does not limit the aggregate amount of indebtedness that may be issued by the Company. The Company's obligations under the Series 2015A Junior Subordinated Notes are subordinate and junior in right of payment to all of the Company's Senior Indebtedness. This means that the Company cannot make any payments on the Series 20I5A Junior Subordinated Notes until all holders of Senior Indebtedness have been paid in full, or provision has been made for such payment, if such Senior Indebtedness is in default (subject to certain exceptions for grace periods and waivers). The indenture under which the Series 2015A Junior Subordinated Notes will be issued does not limit the aggregate amount of Senior Indebtedness that may be issued by the Company. As of Lune 30, 2015, Senior Indebtedness of the Company, on an unconsolidated basis, aggregated approximately $2.9 billion. Since the Company is a holding company, the right of the Company and, hence, the right of creditors of the Company (including holders of Series 2015A Junior Subordinated Notes) to participate in any distribution of the assets of any subsidiary of the Company, whether upon liquidation, reorganization or otherwise, is structurally subordinate to the claims of creditors and preferred and preferences stockholders of each subsidiary. As of June 30, 2015, on a consolidated basis, the Company had approximately $26.3 billion of outstanding long-term debt (including securities due within one year), of which approximately $23.6 billion was long-term debt (including securities due within one year) of the Company's subsidiaries. In addition, the Company had approximately $1.1 billion of short-term notes payable, of which approximately $0.9 billion was short-term notes payable of the Company's subsidiaries. In addition, as of tune 30, 2015, the Company's subsidiaries had approximately $0.7 billion of preferred and preference stock outstanding. The Company may elect to defer interest payments on the Series 20I5A Junior Subordinated Notes at its option for one or more periods of up to 40 consecutive quarterly periods. This may affect the market price of the Series 20I5A Junior Subordinated Notes. The Company may elect at its option to defer payment of all or part of the current and accrued interest otherwise due on the Series 2015A Junior Subordinated Notes for up to 40 consecutive quarterly periods, as described under "Description of the Series 20I5A Junior Subordinated Notes—Option to Defer Interest Payments" in this Prospectus Supplement. At the end of an Optional Deferral Period, if all amounts due are paid, the Company could start a new Optional Deferral Period of up to 40 consecutive quarterly periods. During any Optional Deferral Period, interest on the Series 2015A Junior Subordinated Notes would be deferred but would accrue additional interest at a rate equal to the interest rate then applicable to the Series 2015A Junior Subordinated Notes, compounded quarterly, to the extent permitted by applicable law. No Optional Deferred Period may extend beyond the maturity date or redemption date, if earlier, of the Series 2015A Junior Subordinated Notes. If the Company exercises this interest deferral right, the Series 20I5A Junior Subordinated Notes may trade at a price that does not fully reflect the value of accrued but unpaid interest on the Series 2015A Junior Subordinated Notes or that is otherwise less than the price at which the Series 20I5A Junior Subordinated Notes may have been traded if the Company had not exercised such right. In addition, as a result of the Company's right to defer interest payments, the market price of the Series 2015A Junior Subordinated Notes may be more volatile than other securities that do not have these rights. Holders of the Series 20I5A Junior Subordinated Notes may have to pay taxes on interest before they receive payments from the Company. If the Company defers interest payments on the Series 2015A Junior Subordinated Notes, a holder of the Series 2015A Junior Subordinated Notes will be required to accrue interest income for United States federal income tax purposes in respect of such holder's proportionate share of the accrued but unpaid interest on the Series 20I5A Junior Subordinated Notes, even if such holder normally reports income when received. As a result, a holder will be required to include the accrued interest in such holder's gross income for United States federal income tax purposes before receiving payment of the interest. If a holder sells its Series 20I5A Junior Subordinated Notes before the record date for the first interest payment after an Optional Deferral Period, the accrued interest will be paid to the holder of record on the record date, and the holder will never receive the cash from the S-8 EFTA01121426 Company related to the accrued interest that was reported for tax purposes. Holders should consult with their own tax advisor regarding the tax consequences of an investment in the Series 2015A Junior Subordinated Notes. For more information regarding the tax consequences of purchasing the Series 20I5A Junior Subordinated Notes, see "Material United States Federal Income Tax Considerations" in this Prospectus Supplement. An active trading market for the Series 2015A Junior Subordinated Notes may not develop, and any such market may be illiquid. The Series 20I5A Junior Subordinated Notes constitute a new issue of securities with no established trading market. The Company intends to apply to list the Series 2015A Junior Subordinated Notes on the New York Stock Exchange. If the application is approved, trading on the New York Stock Exchange is expected to commence within 30 days after the date that the Series 2015A Junior Subordinated Notes are first issued. However, listing the Series 2015A Junior Subordinated Notes on the New York Stock Exchange does not guarantee that a trading market will develop or, if a trading market does develop, the depth or liquidity of that market or the ability of holders to sell their Series 2015A Junior Subordinated Notes easily. In addition, the liquidity of the trading market in the Series 2015A Junior Subordinated Notes, and the market prices quoted therefor, may be adversely affected by changes in the overall market for this type of security and by changes in the Company's financial performance or prospects or in the prospects for companies in the Company's industry generally. As a result, the Company cannot assure holders that an active after-market for the Series 2015A Junior Subordinated Notes will develop or be sustained or that holders of the Series 20I5A Junior Subordinated Notes will be able to sell their Series 20I5A Junior Subordinated Notes at favorable prices or at all. Rating agencies may change their practices for rating the Series 2015A Junior Subordinated Notes, which change may affect the market price of the Series 2015A Junior Subordinated ,Votes. In addition, the Company may redeem the Series 20154 Junior Subordinated Notes if a rating agency makes certain changes in the equity credit methodology for securities such as the Series 2015A Junior Subordinated Notes. The rating agencies that currently or may in the future publish a rating for the Company, including Moody's Investors Service, Inc., Standard & Poor's Ratings Services and Fitch Ratings, Inc., may, from time to time in the future, change the way they analyze securities with features similar to the Series 2015A Junior Subordinated Notes. This may include, for example, changes to the relationship between ratings assigned to an issuer's senior securities and ratings assigned to securities with features similar to the Series 2015A Junior Subordinated Notes. If the rating agencies change their practices for rating these types of securities in the future, and the ratings of the Series 20I5A Junior Subordinated Notes are subsequently lowered, that could have a negative impact on the trading price of the Series 2015A Junior Subordinated Notes. In addition, the Company may redeem the Series 20I5A Junior Subordinated Notes before October 15, 2020 at its option, in whole, but not in part, if a rating agency makes certain changes in the equity credit methodology for securities such as the Series 2015A Junior Subordinated Notes. See "Description of the Series 2015A Junior Subordinated Notes—Right to Redeem Upon a Rating Agency Event" in this Prospectus Supplement. SELECTED FINANCIAL INFORMATION The following selected financial data for the years ended December 31, 2010 through December 31, 2014 has been derived from the Company's audited consolidated financial statements and related notes and the unaudited selected financial data, incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The following selected financial data for the six months ended June 30, 2015 has been derived from the Company's unaudited consolidated financial statements and related notes, incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The information set forth below is qualified in its entirety by reference to and, therefore, should be read together with management's discussion and analysis of results of operations and financial condition, the consolidated financial statements and related notes and other financial information incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The information set forth below does not reflect the issuance of the Series 2015A Junior Subordinated Notes offered hereby or the use of proceeds therefrom. See "Use of Proceeds" in this Prospectus Supplement. Six Months Ended Year Ended December 31, June 30, 2010 2011 2012 2013 2014 2015(1) (Millions, except ratios) Operating Revenues $17,456 $17,657 $16,537 $17,087 $18,467 $ 8,520 Consolidated Net Income After Dividends on Preferred and Preference Stock of Subsidiaries 1,975 2,203 2,350 1,644 1,963 1,138 Ratio of Earnings to Fixed Charges(2) 3.43 3.87 4.13 3.14 3.43 3.97 S-9 EFTA01121427 Capitalization as of June 30, 2015 Actual As Adjusted(3) (Millions, except percentages) Common Stockholders' Equity $20,182 520,182 45.2% Preferred and Preference Stock of Subsidiaries 609 609 1.3 Noncontrolling Interest 355 355 0.8 Redeemable Preferred Stock of Subsidiaries 118 118 0.3 Senior Notes 16,988 16,928 37.9 Other Long-Term Debt 5,686 6,486 14.5 Total, excluding amounts due within one year of $3.6 billion $43,938 $44,678 100.0% (I) Due to seasonal variations in demand for energy, operating results for the six months ended June 30, 2015 do not necessarily indicate operating results for the entire year. (2) This ratio is computed as follows: (i) "Earnings" have been calculated by adding to "Earnings Before Income Taxes" "Interest expense, net of amounts capitalized," the interest component of rental expense, the amortization of capitalized interest and the debt portion of allowance for funds used during construction, less "Dividends on Preferred and Preference Stock of Subsidiaries" and (ii) "Fixed Charges" consist of interest expense, capitalized interest, "Dividends on Preferred and Preference Stock of Subsidiaries," the interest component of rental expense and the debt portion of allowance for funds used during construction. In computing "Fixed Charges," "Dividends on Preferred and Preference Stock of Subsidiaries" represent the before tax earnings necessary to pay such dividends, computed at the effective tax rates for the applicable periods. (3) Reflects adjustments to "Other Long-Term Debt" related to (i) a 13-month variable rate bank term loan in an aggregate principal amount outstanding of $400,000,000 entered into by Southern Power Company in August 2015 and (ii) an l8-month variable rate bank term loan in an aggregate principal amount outstanding of $400,000,000 entered into by the Company in September 2015. Also reflects an adjustment to "Senior Notes" related to the redemption in September 2015 of $60,000,000 aggregate principal amount of Gulf Power Company's Series L 5.65% Senior Notes due September 1, 2035. USE OF PROCEEDS The net proceeds from the sale of the Series 20I5A Junior Subordinated Notes will be used by the Company to pay a portion of its outstanding short-term indebtedness, which aggregated approximately $524,000,000 as of September 30, 2015, and for other general corporate purposes, including investment by the Company in its subsidiaries. DESCRIPTION OF THE SERIES 2015A JUNIOR SUBORDINATED NOTES Set forth below is a description of the specific terms of the Series 2015A % Junior Subordinated Notes due October IS, 2075 (the "Series 20I5A Junior Subordinated Notes"). This description supplements, and should be read together with, the description of the general terms and provisions of the junior subordinated notes set forth in the accompanying Prospectus under the caption "Description of the Junior Subordinated Notes." The following description does not purport to be complete and is subject to, and is qualified in its entirety by reference to, the description in the accompanying Prospectus. General The Series 20I5A Junior Subordinated Notes will be issued as a series of junior subordinated notes under a Subordinated Note Indenture, as supplemented (the "Subordinated Note Indenture"), to be entered into between the Company and Wells Fargo Bank, National Association, as trustee (the "Subordinated Note Indenture Trustee"). The Series 2015A Junior Subordinated Notes will initially be issued in the aggregate principal amount of $ . The Company may, at any time and without the consent of the holders of the Series 20I5A Junior Subordinated Notes, issue additional notes having the same ranking and the same interest rate, maturity and other terms as the Series 2015A Junior Subordinated Notes (except for the public offering price and issue date and the initial interest accrual date and initial Interest Payment Date (as defined below), if applicable). Any additional notes having such similar terms, together with the Series 20I5A Junior Subordinated Notes, will constitute a single series of junior subordinated notes under the Subordinated Note Indenture. S-10 EFTA01121428 In addition, the Company has granted the underwriters an option to purchase up to an additional $ in principal amount of the Series 20I5A Junior Subordinated Notes in order to cover over-allotments, if any. Unless earlier redeemed, the entire principal amount of the Series 20I5A Junior Subordinated Notes will mature and become due and payable, together with any accrued and unpaid interest thereon, on October 15, 2075. The Series 20I5A Junior Subordinated Notes are not subject to any sinking fund provision. The Series 2015A Junior Subordinated Notes are available for purchase in denominations of $25.00 and integral multiples of $25.00 in excess thereof. Interest Each Series 20I5A Junior Subordinated Note will bear interest at the rate of % per annum (the "Securities Rate") from the date of original issuance. Subject to the Company's right to defer interest payments as described below, interest on the Series 20I5A Junior Subordinated Notes will be payable quarterly in arrears on January 15, April 15, July 15 and October 15 of each year (each, an "Interest Payment Date") to the person in whose name such Series 20I5A Junior Subordinated Note is registered at the close of business (i) on the Business Day immediately preceding such Interest Payment Date if the Series 2015A Junior Subordinated Notes are in book-entry only form or (ii) on the 15th calendar day preceding such Interest Payment Date if the Series 20I5A Junior Subordinated Notes are not in book-entry only form (whether or not a Business Day). The initial Interest Payment Date is January 15, 2016. The amount of interest payable will be computed on the basis of a 360-day year of twelve 30- day months. In the event that any date on which interest is payable on the Series 2015A Junior Subordinated Notes is not a Business Day, then payment of the interest payable on such date will be made on the next succeeding day which is a Business Day (and without any interest or other payment in respect of any such delay), with the same force and effect as if made on such date. "Business Day" means a day other than (i) a Saturday or Sunday, (ii) a day on which banks in New York, New York are authorized or obligated by law or executive order to remain closed or (iii) a day on which the Subordinated Note Indenture Trustee's corporate trust office is closed for business. Option to Defer Interest Payments So long as no Event of Default under the Subordinated Note Indenture has occurred and is continuing, at the Company's option, it may, on one or more occasions, defer payment of all or part of the current and accrued interest otherwise due on the Series 20I5A Junior Subordinated Notes by extending the interest payment period for up to 40 consecutive quarterly periods (each period, commencing on the date that the first such interest payment would otherwise have been made, an "Optional Deferral Period"). A deferral of interest payments may not extend beyond the maturity date of the Series 2015A Junior Subordinated Notes or end on a day other than an Interest Payment Date. Any deferred interest on the Series 20I5A Junior Subordinated Notes will accrue additional interest at the Securities Rate from the applicable Interest Payment Date to the date of payment, compounded quarterly (such deferred interest and additional interest accrued thereon, "Additional Interest"), to the extent permitted under applicable law. No interest will be due and payable on the Series 20I5A Junior Subordinated Notes until the end of an Optional Deferral Period, except upon a redemption of the Series 2015A Junior Subordinated Notes during such Optional Deferral Period. At the end of an Optional Deferral Period or on any redemption date, the Company will be obligated to pay all accrued and unpaid interest, including any Additional Interest. Once the Company pays all accrued and unpaid interest payments on the Series 20I5A Junior Subordinated Notes, including any Additional Interest, the Company can again defer interest payments on the Series 20I5A Junior Subordinated Notes as described above, but not beyond the maturity date of the Series 2015A Junior Subordinated Notes. The Company is required to provide to the Subordinated Note Indenture Trustee written notice of any optional deferral of interest at least 10 and not more than 60 Business Days prior to the earlier of (1) the next applicable Interest Payment Date or (2) the date, if any, upon which it is required to give notice of such Interest Payment Date or the record date therefor to the New York Stock Exchange or any applicable self-regulatory organization. In addition, the Company is required to deliver to the Subordinated Note Indenture Trustee an officers' certificate stating that no default or Event of Default shall have occurred and be continuing. Subject to receipt of the officers' certificate, the Subordinated Note Indenture Trustee is required to promptly forward such notice to each holder of record of Series 20I5A Junior Subordinated Notes. Certain Limitations During an Optional Deferral Period During an Optional Deferral Period, subject to the exceptions noted below, the Company shall not: declare or pay any dividend or make any distributions with respect to, or redeem, purchase, acquire or make a liquidation payment with respect to, any of its capital stock, or S-11 EFTA01121429 make any payment of interest, principal or premium, if any, on or repay, repurchase or redeem any debt securities (including guarantees) issued by the Company which rank equally with or junior to the Series 2015A Junior Subordinated Notes. None of the foregoing, however, shall restrict: • any of the actions described in the preceding sentence resulting from any reclassification of the Company's capital stock or the exchange or conversion of one class or series of the Company's capital stock for another class or series of the Company's capital stock; • the purchase of fractional interests in shares of the Company's capital stock pursuant to the conversion or exchange provisions of such capital stock or the security being converted or exchanged; • dividends, payments or distributions payable in shares of capital stock; • redemptions, purchases or other acquisitions of shares of capital stock in connection with any employment contract, incentive plan, benefit plan or other similar arrangement of the Company or any of its subsidiaries or in connection with a dividend reinvestment or stock purchase plan; or • any declaration of a dividend in connection with implementation of any stockholders' rights plan, or the issuance of rights, stock or other property under any such plan, or the redemption, repurchase or other acquisition of any such rights pursuant thereto. Optional Redemption At any time and from time to time on or after October 15, 2020, the Series 2015A Junior Subordinated Notes will be subject to redemption at the option of the Company in whole or in part upon not less than 30 nor more than 60 days' notice, at a redemption price equal to 100% of the principal amount of the Series 2015A Junior Subordinated Notes being redeemed plus accrued and unpaid interest (including any Additional Interest) on the Series 2015A Junior Subordinated Notes being redeemed to the redemption date. If notice of redemption is given as aforesaid, the Series 20I5A Junior Subordinated Notes so to be redeemed will, on the redemption date, become due and payable at the redemption price together with any accrued and unpaid interest thereon, and from and after such date (unless the Company has defaulted in the payment of the redemption price and accrued interest) such Series 20 I5A Junior Subordinated Notes shall cease to bear interest. If any Series 2015A Junior Subordinated Note called for redemption shall not be paid upon surrender thereof for redemption, the principal shall, until paid, bear interest from the redemption date at the Securities Rate. See "Description of the Junior Subordinated Notes — Events of Default" in the accompanying Prospectus. The Company may also redeem the Series 2015A Junior Subordinated Notes before October IS, 2020 (i) in whole, but not in part, if certain changes in tax laws, regulations or interpretations occur, at the redemption price and under the circumstances described below under "—Right to Redeem Upon a Tax Event" and (ii) in whole, but not in part, if a rating agency makes certain changes in the equity credit criteria for securities such as the Series 2015A Junior Subordinated Notes, at the redemption price and under the circumstances described below under "—Right to Redeem Upon a Rating Agency Event." Subject to the foregoing and to applicable law (including, without limitation, United States federal securities laws), the Company or its affiliates may, at any time and from time to time, purchase outstanding Series 2015A Junior Subordinated Notes by tender, in the open market or by private agreement. Right to Redeem Upon a Tax Event Before October 15, 2020, the Company may redeem, upon a redemption notice, in whole but not in part, the Series 2015A Junior Subordinated Notes following the occurrence of a Tax Event (as defined below), at 100% of their principal amount plus any accrued and unpaid interest thereon (including any Additional Interest) to the redemption date. A "Tax Event" happens when the Company has received an opinion of counsel experienced in tax matters that, as a result of: • any amendment to, clarification of, or change, including any announced prospective change, in the laws or treaties of the United States or any of its political subdivisions or taxing authorities, or any regulations under those laws or treaties; • an administrative action, which means any judicial decision or any official administrative pronouncement, ruling, regulatory procedure, notice or announcement including any notice or announcement of intent to issue or adopt any administrative pronouncement, ruling, regulatory procedure or regulation; S-I2 EFTA01121430 • any amendment to, clarification of, or change in the official position or the interpretation of any administrative action or judicial decision or any interpretation or pronouncement that provides for a position with respect to an administrative action or judicial decision that differs from the previously generally accepted position, in each case by any legislative body, court, governmental authority or regulatory body, regardless of the time or manner in which that amendment, clarification or change is introduced or made known; or a threatened challenge asserted in writing in connection with the Company's audit or an audit of any of its subsidiaries, or a publicly-known threatened challenge asserted in writing against any other taxpayer that has raised capital through the issuance of securities that are substantially similar to the Series 2015A Junior Subordinated Notes, which amendment, clarification or change is effective or the administrative action is taken or judicial decision, interpretation or pronouncement is issued or threatened challenge is asserted or becomes publicly-known after the date of the original issuance of the Series 2015A Junior Subordinated Notes, there is more than an insubstantial risk that interest payable by us on the Series 2015A Junior Subordinated Notes is not deductible, or within 90 days would not be deductible, in whole or in part, by us for United States federal income tax purposes. Right to Redeem Upon a Rating Agency Event Before October 15, 2020, the Company may redeem, upon a redemption notice, in whole but not in part, the Series 2015A Junior Subordinated Notes following the occurrence of a Rating Agency Event (as defined below), at 102% of their principal amount plus any accrued and unpaid interest thereon (including any Additional Interest) to the redemption date. "Rating Agency Event" means a change to the methodology or criteria that were employed by an applicable nationally recognized statistical rating organization for purposes of assigning equity credit to securities such as the Series 20 I5A Junior Subordinated Notes on the date of original issuance of the Series 2015A Junior Subordinated Notes (the "current methodology"), which change either (i) shortens the period of time during which equity credit pertaining to the Series 20 I5A Junior Subordinated Notes would have been in effect had the current methodology not been changed or (ii) reduces the amount of equity credit assigned to the Series 2015A Junior Subordinated Notes as compared with the amount of equity credit that such rating agency had assigned to the Series 2015A Junior Subordinated Notes as of the date of original issuance thereof. Ranking The Company's payment obligations under the Series 2015A Junior Subordinated Notes will be unsecured and will rank junior and be subordinated in right of payment and upon liquidation to all of its Senior Indebtedness, whether presently existing or from time to time hereafter incurred, created, assumed or existing. See "Description of the Junior Subordinated Notes — Subordination" in the accompanying Prospectus. Events of Default The following are the "Events of Default" with respect to the Series 2015A Junior Subordinated Notes, which are modified from the events of default described in the accompanying Prospectus: failure to pay principal of, or premium, if any, on or interest on the Series 2015A Junio