GUARANTEE AGREEMENT NEXITY FINANCIAL CORPORATION

Exhibit 10.3

GUARANTEE AGREEMENT

NEXITY FINANCIAL CORPORATION

JUNE 20, 2008

TABLE OF CONTENTS

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GUARANTEE AGREEMENT

This GUARANTEE AGREEMENT (the “Guarantee”), dated as of June 20, 2008, is executed and delivered by Nexity Financial Corporation, a Delaware corporation (the “Guarantor”), and Wilmington Trust Company, a Delaware banking corporation, as trustee (the “Guarantee Trustee”), for the benefit of the Holders (as defined herein) from time to time of the Preferred Securities (as defined herein) of Nexity Capital Trust III, a Delaware statutory business trust (the “Issuer”).

WHEREAS, pursuant to an Amended and Restated Trust Agreement (the “Trust Agreement”), dated as of June 20, 2008, among the trustees of the Issuer, the Guarantor, and the holders from time to time of undivided beneficial interests in the assets of the Issuer, the Issuer (i) is issuing on the date hereof up to 10,000 preferred securities, having an aggregate liquidation amount of up to $10,000,000, such preferred securities being designated the Floating Rate Preferred Securities (collectively, the “Preferred Securities”).

WHEREAS, as incentive for the Holders to purchase the Preferred Securities, the Guarantor desires irrevocably and unconditionally to agree, to the extent set forth in this Guarantee, to pay to the Holders of the Preferred Securities the Guarantee Payments (as defined below). The Guarantor agrees to make certain other payments on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the purchase by each Holder of Preferred Securities, which purchase the Guarantor hereby acknowledges shall benefit the Guarantor, the Guarantor executes and delivers this Guarantee for the benefit of the Holders.

ARTICLE I

DEFINITIONS AND INTERPRETATION

SECTION 1.1 Definitions and Interpretation

In this Guarantee, unless the context otherwise requires:

(a) capitalized terms used in this Guarantee but not defined in the preamble above have the respective meanings assigned to them in this Section 1.1;

(b) terms defined in the Trust Agreement as of the date of execution of this Guarantee have the same meaning when used in this Guarantee unless otherwise defined in this Guarantee;

(c) a term defined anywhere in this Guarantee has the same meaning throughout;

(d) all references to “the Guarantee” or “this Guarantee” are to this Guarantee as modified, supplemented or amended from time to time;

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(e) all references in this Guarantee to Articles and Sections are to Articles and Sections of this Guarantee, unless otherwise specified; and

(f) a reference to the singular includes the plural and vice versa.

As used in this Guarantee Agreement, the terms set forth below shall, unless the context otherwise requires, have the following meanings:

“ Affiliate ” has the same meaning as given to that term in Rule 405 under the Securities Act of 1933, as amended, or any successor rule thereunder.

“ Business Day ” means any day other than a Saturday or a Sunday, or a day on which banking institutions in the City of New York, Wilmington, Delaware or Birmingham, Alabama are authorized or required by law or executive order to close.

“ Common Securities ” means the securities representing common undivided beneficial interests in the assets of the Issuer.

“ Corporate Trust Office ” means the office of the Guarantee Trustee at which the corporate trust business of the Guarantee Trustee shall, at any particular time, be principally administered, which office at the date of execution of this Agreement is located at Wilmington Trust Company, Rodney Square North, 1100 North Market Street, Wilmington, Delaware 19890, Attention: Corporate Trust Administration.

“ Covered Person ” means any Holder or beneficial owner of Preferred Securities.

“ Event of Default ” means a default by the Guarantor on any of its payment or other obligations under this Guarantee; provided, that except with respect to a default in payment of any Guarantee Payments, the Guarantor shall have received notice of default from the Guarantee Trustee and shall not have cured such default within thirty (30) days after receipt of such notice.

“ Guarantee Payments ” means the following payments or distributions, without duplication, with respect to the Preferred Securities, to the extent not paid or made by the Issuer: (i) any accumulated and unpaid Distributions (as defined in the Trust Agreement) that are required to be paid on such Preferred Securities to the extent the Issuer has funds on hand legally available therefor at such time, (ii) the prepayment price, including all accumulated and unpaid Distributions to the date of prepayment (the “Prepayment Price”) to the extent the Issuer has funds on hand legally available therefor at such time, with respect to any Preferred Securities called for prepayment by the Issuer, and (iii) upon a voluntary or involuntary termination and liquidation of the Issuer (other than in connection with the distribution of Notes to the Holders in exchange for Preferred Securities as provided in the Trust Agreement), the lesser of (a) the aggregate of the liquidation amount and all accumulated and unpaid Distributions on the Preferred Securities to the date of payment, to the extent the Issuer has funds on hand legally available therefor, and (b) the amount of assets of the Issuer remaining available for distribution to Holders in liquidation of the Issuer after satisfaction of liabilities to creditors of the Issuer in accordance with applicable law.

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“ Guarantee Trustee ” means Wilmington Trust, until a Successor Guarantee Trustee has been appointed and has accepted such appointment pursuant to the terms of this Guarantee and thereafter means each such Successor Guarantee Trustee.

“ Holder ” shall mean any holder, as registered on the books and records of the Issuer, of any Preferred Securities; provided, however, that, in determining whether the holders of the requisite percentage of Preferred Securities have given any request, notice, consent or waiver hereunder, “Holder” shall not include the Guarantor or any Affiliate of the Guarantor.

“ Indemnified Person ” means the Guarantee Trustee, any Affiliate of the Guarantee Trustee, or any officers, directors, shareholders, members, partners, employees, representatives, nominees, custodians or agents of the Guarantee Trustee.

“ Indenture ” means the Indenture dated as of June 20, 2008, between the Guarantor (the “Note Issuer”) and Wilmington Trust, as trustee, pursuant to which the Notes are to be issued to the Property Trustee of the Issuer.

“ Majority in liquidation amount of the Preferred Securities ” means a vote by Holder(s) of Preferred Securities, voting separately as a class, of more than 50% of the aggregate liquidation amount (including the stated amount that would be paid on prepayment, liquidation or otherwise, plus accumulated and unpaid Distributions to the date upon which the voting percentages are determined) of all Preferred Securities.

“ Notes ” means the series of subordinated debt securities of the Guarantor designated the Floating Rate Junior Subordinated Deferrable Interest Notes due July 1, 2038 held by the Property Trustee (as defined in the Trust Agreement) of the Issuer.

“ Officers’ Certificate ” means, with respect to any person, a certificate signed by two of the following: the Chairman, a Vice Chairman, the Chief Executive Officer, the President, a Vice President, the Controller, the Secretary, an Assistant Secretary, the Treasurer or Assistant Treasurer of the Guarantor. Any Officers’ Certificate delivered with respect to compliance with a condition or covenant provided for in this Guarantee shall include:

(a) a statement that each officer signing the Officers’ Certificate has read the covenant or condition and the definitions relating thereto;

(b) a brief statement of the nature and scope of the examination or investigation undertaken by each officer in rendering the Officer’s Certificate;

(c) a statement that each such officer has made such examination or investigation as, in such officer’s opinion, is necessary to enable such officer to express an informed opinion as to whether or not such covenant or condition has been complied with; and

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(d) a statement as to whether, in the opinion of each such officer, such condition or covenant has been complied with.

“ Other Notes ” means all junior subordinated notes issued by the Guarantor from time to time and sold to trusts to be established by the Guarantor (if any), in each case similar to the Issuer.

“ Other Guarantees ” means all guarantees hereafter issued by the Guarantor with respect to preferred securities (if any) similar to the Preferred Securities issued by other trusts to be established by the Guarantor (if any), in each case similar to the Issuer.

“ Person ” means a legal person, including any individual, corporation, estate, partnership, joint venture, association, joint stock company, limited liability company, trust, unincorporated association, or government or any agency or political subdivision thereof, or any other entity of whatever nature.

“ Responsible Officer ” means, with respect to the Guarantee Trustee, any officer assigned to the Corporate Trust Office with direct responsibility for administration of the Trust, including any Managing Director, Vice President, Assistant Vice President, Assistant Treasurer, Assistant Secretary or any other officer of the Guarantee Trustee customarily performing functions similar to those performed by any of the above designated officers and also means, with respect to a particular matter, any other officer to whom such matter is referred because of that officer’s knowledge of and familiarity with the particular subject.

“ Successor Guarantee Trustee ” means a successor Guarantee Trustee possessing the qualifications to act as Guarantee Trustee under Section 4.1.

“ Trust Indenture Act ” means the Trust Indenture Act of 1939, as amended.

“ Trust Securities ” means the Common Securities and the Preferred Securities.

ARTICLE II

TRUST INDENTURE ACT

SECTION 2.1 Trust Indenture Act; Application

This Guarantee is not subject to the provisions of the Trust Indenture Act.

SECTION 2.2 Lists of Holders of Securities; Guarantee Trustee as Creditor

(a) The Guarantor shall provide the Guarantee Trustee (unless the Guarantee Trustee is otherwise the registrar of the Preferred Securities) with a list, in such form as the Guarantee Trustee may reasonably require, of the names and addresses of the Holders of the Preferred Securities (“List of Holders”) as of such date, (i) within one Business Day after December 15 and June 15 of each year, and (ii) at any other time within 30 days of receipt by the Guarantor of

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a written request for a List of Holders as of a date no more than 14 days before such List of Holders is given to the Guarantee Trustee; provided, that the Guarantor shall not be obligated to provide such List of Holders at any time the List of Holders does not differ from the most recent List of Holders given to the Guarantee Trustee by the Guarantor. The Guarantee Trustee may destroy any List of Holders previously given to it on receipt of a new List of Holders.

(b) Subject to the provisions of subsection (c) of this section 2.2, if the Guarantee Trustee shall be, or shall become, a creditor, directly or indirectly, secured or unsecured, of the Guarantor, within three months prior to any failure to make payment in full of any Guarantee payment under this Guarantee, or subsequent to such a default, then, unless and until such default shall be cured, the Guarantee Trustee shall set apart and hold in a special account for the benefit of the Guarantee Trustee individually and the Holders:

(1) An amount equal to any and all reductions in the amount due and owing upon any claim as such creditor in respect of principal or interest, effected after the beginning of such three months’ period and valid as against Guarantor and its creditors, except any such reduction resulting from the receipt or disposition of any property described in paragraph (2) of this subsection, or from the exercise of any right of set-off which the Guarantee Trustee could have exercised if a petition in bankruptcy had been filed by or against Guarantor upon the date of such default.

(2) All property received in respect of any claim as such creditor, either as security therefor, or in satisfaction or compromise thereof, or otherwise, after the beginning of such three months’ period, of an amount equal to the proceeds or any such property, if disposed of, subject, however, to the rights, if any, of Guarantor and its other creditors in such property or such proceeds.

(3) Nothing herein contained shall affect the right of the Guarantee Trustee:

(A) To retain for its own account (a) payments made on account of any such claim by any person (other than Guarantor) who is liable thereon, and (b) the proceeds of the bona fide sale of any such claim by the Guarantee Trustee to a third person, and (c) distributions made in cash, securities, or other property in respect of claims filed against Guarantor in bankruptcy or receivership or in proceedings for reorganization pursuant to the Federal Bankruptcy Act or applicable state law;

(B) To realize, for its own account, upon any property held by it as security for any such claim, if such property was so held prior to the beginning of such three-months’ period;

(C) To realize, for its own account, but only to the extent of the claim hereinafter mentioned, upon any property held by it as security for any such claim, if such claim was created after the beginning of such three months’ period and such property was received as security therefor simultaneously with the creation thereof, and if the Guarantee Trustee shall sustain the burden of proving that at the time such property was so received the Guarantee Trustee had no reasonable cause to believe that a default would occur within three months; or

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(D) To receive payment on any claim referred to in paragraph (B) or (C), against the release of property held as security for such claim as provided in paragraph (B) or (C), as the case may be, to the extent of the fair value of such property.

For the purposes of paragraphs (B), (C) and (D), property substituted after the beginning of such three-months’ period for property held as security at the time of such substitution shall, to the extent of the fair value of the property released, have the same status as the property released, and, to the extent that any claim referred to in any of such paragraphs is created in renewal of or in substitution for or for the purpose of repaying or refunding any preexisting claim of the Guarantee Trustee as such creditor, such claim shall have the same status as such preexisting claim.

(4) If the Guarantee Trustee shall be required to account for any Securities held, the funds and property held in such special account and the proceeds thereof shall be apportioned between the Guarantee Trustee and the Holders in such manner that the Guarantee Trustee and the Holders realize, as a result of payments from such special account and payments of dividends on claims filed against the Guarantor in bankruptcy or receivership or in proceedings for reorganization pursuant to the Federal Bankruptcy Act or applicable state law, the same percentage of their respective claims, figured before crediting to the claim of the Guarantee Trustee anything on account of the receipt by it from such obligor of the funds and property in such special account and before crediting to the respective claims of the Guarantee Trustee and the Holders dividends on claims filed against the Guarantor in bankruptcy or receivership or in proceedings for reorganization pursuant to the Federal Bankruptcy Act or applicable state law, but after crediting thereon receipts on account of the indebtedness represented by their respective claims from all sources other than from such dividends and from the funds and property so held in such special account. As used in this paragraph, with respect to any claim, the term “dividends” shall include any distributions with respect to such claim, in bankruptcy or receivership or in proceedings for reorganization pursuant to the Federal Bankruptcy Act or applicable state law, whether such distribution is made in cash, securities, or other property, but shall not include any such distribution with respect to the secured portion, if any, of such claim. The court in which such bankruptcy, receivership or proceeding for reorganization is pending shall have jurisdiction (i) to apportion between the Guarantee Trustee and the Holders, in accordance with the provisions of this paragraph, the funds and property held in such special account and the proceeds thereof, or (ii) in lieu of such apportionment, in whole or in part, to give to the provisions of this paragraph due consideration in determining the fairness of the distributions to be made to the Guarantee Trustee and the Holders with respect to their respective claims, in which event it shall not be necessary to liquidate or to appraise the value of any securities or other property held in such special account or as security for any such claim, or to make a specific allocation of such distributions as between the secured and unsecured portions of such claims, or otherwise to apply the provisions of this paragraph as a mathematical formula.

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(5) Any Guarantee Trustee who has resigned or been removed after the beginning of such three months’ period shall be subject to the provisions of this subsection as though such resignation or removal had not occurred. Any Guarantee Trustee who has resigned or been removed prior to the beginning of such three months’ period shall be subject to the provisions of this subsection if and only if the following conditions exist (i) the receipt of property or reduction of claim which would have given rise to the obligation to account, if such Guarantee Trustee had continued as trustee, occurred after the beginning of such three-months’ period; and (ii) such receipt of property or reduction of claim occurred within three months after such resignation or removal.

(c) Creditor relationships arising from the following shall be excluded from the provisions of 2.2(b):

(1) The ownership or acquisition of securities issued under any indenture, or any security or securities having a maturity of one year or more at the time of acquisition by the Guarantee Trustee;

(2) Advances authorized by a receivership or bankruptcy court of competent jurisdiction for the purpose of discharging tax liens or other prior liens or encumbrances on the trust estate, if notice of such advance and of the circumstances surrounding the making thereof is given to the Holders;

(3) Disbursements made in the ordinary course of business in the capacity of trustee under an indenture, transfer agent, registrar, custodian, paying agent, fiscal agent or depositary, or other similar capacity;

(4) An indebtedness created as a result of services rendered or premises rented; or an indebtedness created as a result of goods or securities sold in a cash transaction;

(5) The ownership of stock or of other securities of a corporation organized under the provisions of Section 25(a) of the Federal Reserve Act, as amended, which is directly or indirectly a creditor of the Guarantor upon the Trust Securities; or

(6) The acquisition, ownership, acceptance, or negotiation of any drafts, bills of exchange, acceptances, or obligations which fall within the classification of self-liquidating paper.

(d) Within five Business Days after the receipt by the Guarantee Trustee of a written application by three or more Holders stating that the applicants desire to communicate with other holders of Preferred Securities with respect to their rights under such Guarantee or under the Preferred Securities, and accompanied by a copy of the form of proxy or other communication which such applicants propose to transmit, and by reasonable proof that each such applicant has owned a Preferred Security for a period of at least six months preceding the date of such application, such Guarantee Trustee shall, at its election, either:

(1) Afford to such applicants access to all information so furnished to or received by the Guarantee Trustee; or

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(2) Inform such applicants as to the approximate number of Holders according to the most recent information so furnished to or received by the Guarantee Trustee, and as to the approximate cost of mailing to such Holders the form of proxy or other communication, if any, specified in such application.

If the Guarantee Trustee shall elect not to afford to such applicants access to such information, the Guarantee Trustee shall, upon the written request of such applicants, mail to all such Holders copies of the form of proxy or other communication which is specified in such request, with reasonable promptness after a tender to the Guarantee Trustee of the material to be mailed and of payment, or provision for the payment, of the reasonable expenses of such mailing, unless within five Business Days after such tender, the Guarantee Trustee shall mail to such applicants, a written statement to the effect that, in the opinion of the Guarantee Trustee, such mailing would be contrary to the best interests of the Holders, or would be in violation of applicable law. Such written statement shall specify the basis of such opinion.

SECTION 2.3 Reports by the Guarantee Trustee

(a) Within 60 days after July 1 of each year, commencing July 1, 2009, the Guarantee Trustee shall provide to the Holders a brief report with respect to any of the following events which may have occurred within the previous 12 months (but if no such event has occurred within such period no report need be transmitted):

(1) The character and amount of any advances made by it, as Guarantee Trustee, which remain unpaid on the date of such report, and for the reimbursement of which it claims or may claim a lien or charge, prior to that of the Preferred Securities, on the trust estate or on property or funds held or collected by it as the Guarantee Trustee, if such advances so remaining unpaid aggregate more than one-half of one per centum of the principal amount of the Preferred Securities outstanding on such date;

(2) Any change to the amount, interest rate, and maturity date of all other indebtedness owning to it in its individual capacity, on the date of such report, by the Guarantor, with a brief description of any property held as collateral security therefor, except an indebtedness based upon a creditor relationship arising in any manner described in Section 2.2(b)(3)(B), (C) or (D);

(3) Any change to the property and funds physically in its possession as Guarantee Trustee on the date of such report;

(4) Any additional issue of Preferred Securities which it has not previously reported; and

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