Exhibit
      4.5


GUARANTEE
      AGREEMENT





BAY
      NATIONAL CORPORATION





Dated
      as
      of December 12, 2005

















**TABLE
      OF CONTENTS**





**Page**





ARTICLE
      I





DEFINITIONS
      AND INTERPRETATION


SECTION
                1.1
            Definitions
                and Interpretation.
            1ARTICLE
                IIPOWERS,
                DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEESECTION
                2.1
            Powers
                and Duties of the Guarantee Trustee.
            4SECTION
                2.2
            Certain
                Rights of the Guarantee Trustee.
            6SECTION
                2.3
            Not
                Responsible for Recitals or Issuance of Guarantee.
            7SECTION
                2.4
            Events
                of Default; Waiver.
            7SECTION
                2.5
            Events
                of Default, Notice.
            8ARTICLE
                IIITHE
                GUARANTEE TRUSTEESECTION
                3.1
            The
                Guarantee Trustee. Eligibility.
            8SECTION
                3.2
            Appointment.
                Removal and Resignation of the Guarantee Trustee.
            9ARTICLE
                IVGUARANTEESECTION
                4.1
            Guarantee.
            10SECTION
                4.2
            Waiver
                of Notice and Demand.
            10SECTION
                4.3
            Obligations
                Not Affected.
            10SECTION
                4.4
            Rights
                of Holders.
            11SECTION
                4.5
            Guarantee
                of Payment.
            12SECTION
                4.6
            Subrogation.
            12SECTION
                4.7
            Independent
                Obligations.
            12SECTION
                4.8
            Enforcement.
            12ARTICLE
                VLIMITATION
                OF TRANSACTION, SUBORDINATIONSECTION
                5.1
            Limitation
                of Transactions.
            13SECTION
                5.2
            Ranking.
            13




i


ARTICLE
                VITERMINATIONSECTION
                6.1
            Termination.
            14ARTICLE
                VIIINDEMNIFICATIONSECTION
                7.1
            Exculpation.
            14SECTION
                7.2
            Indemnification.
            14SECTION
                7.3
            Compensation;
                Reimbursement of Expenses.
            15ARTICLE
                VIIIMISCELLANEOUSSECTION
                8.1
            Successors
                and Assigns.
            16SECTION
                8.2
            Amendments.
            16SECTION
                8.3
            Notices.
            16SECTION
                8.4
            Benefit.
            17SECTION
                8.5
            Governing
                Law.
            17SECTION
                8.6
            Counterparts.
            17














ii


GUARANTEE
      AGREEMENT





This
      GUARANTEE AGREEMENT (the “Guarantee”), dated as of December 12, 2005, is
      executed and delivered by Bay National Corporation, a bank holding company
      incorporated in the State of Maryland (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
      Capital Securities (as defined herein) of Bay National Capital Trust I, a
      Delaware statutory trust (the “Issuer”).





WHEREAS,
      pursuant to an Amended and Restated Declaration of Trust (the “Declaration”),
      dated as of December 12, 2005, among the trustees named therein of the Issuer,
      Bay National Corporation, as sponsor, and the Holders from time to time of
      undivided beneficial interests in the assets of the Issuer, the Issuer is
      issuing on the date hereof securities, having an aggregate liquidation amount
      of
      $8,000,000, designated in the Declaration as MMCapS SM (the
“Capital Securities”); and





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





NOW,
      THEREFORE, in consideration of the purchase by each Holder of the Capital
      Securities, which purchase the Guarantor hereby agrees 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)  a
      term
      defined anywhere in this Guarantee has the same meaning throughout;





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





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








(e)  terms
      defined in the Declaration as of the date of execution of this Guarantee have
      the same meanings when used in this Guarantee, unless otherwise defined in
      this
      Guarantee or unless the context otherwise requires; and





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





“Beneficiaries”
      means any Person to whom the Issuer is or hereafter becomes indebted or
      liable.





“Common
      Securities” has the meaning specified in the Declaration.





“Corporate
      Trust Office” means the office of the Guarantee Trustee at which at any
      particular time its corporate trust business shall be principally administered,
      which at all times shall be located within the United States and at the time
      of
      the execution of this Guarantee shall be Rodney Square North, 1100 North Market
      Street, Wilmington, DE 19890-0001.





“Covered
      Person” means any Holder of Capital Securities.





“Debenture
      Issuer” means Bay National Corporation or any successor entity resulting from
      any consolidation, amalgamation, merger or other business combination, in its
      capacity as issuer of the Debentures.





“Debentures”
      means the junior subordinated debentures of the Debenture Issuer that are
      designated in the Indenture as the “Fixed Rate Junior Subordinated Debt
      Securities due 2036” and held by the Institutional Trustee (as defined in the
      Declaration) of the Issuer.





“Event
      of
      Default” has the meaning set forth in Section 2.4.





“Guarantee
      Payments” means the following payments or distributions, without duplication,
      with respect to the Capital Securities, to the extent not paid or made by the
      Issuer: (i) any accrued and unpaid Distributions (as defined in the
      Declaration) which are required to be paid on such Capital Securities to the
      extent the Issuer has funds available in the Property Account (as defined in
      the
      Declaration) therefor at such time, (ii) the price payable upon the redemption
      of any Capital Securities to the extent the Issuer has funds available in the
      Property Account therefor at such time, with respect to any Capital Securities
      that are (1) called for redemption by the Issuer or (2) mandatorily redeemed
      by
      the Issuer, in each case, in accordance with the terms of such Capital
      Securities, and (iii) upon a voluntary or involuntary liquidation, dissolution,
      winding-up or termination of the Issuer (other than in connection with the
      distribution of Debentures to the Holders of the Capital Securities in exchange
      therefor as provided in the Declaration), the lesser of (a) the aggregate of
      the
      liquidation amount of the Capital Securities and all accrued and unpaid
      Distributions on the Capital Securities to the date of payment, to the extent
      the Issuer has funds available in the Property Account therefor at such time,
      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 as required by applicable law (in either case, the
      “Liquidation Distribution”).





2


“Guarantee
      Trustee” means Wilmington Trust Company, 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”
      means any Person in whose name any Capital Securities are registered on the
      books and records of the Issuer; provided , however ,
      that,
      in determining whether the holders of the requisite percentage of Capital
      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 (including in its individual capacity), 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 December 12, 2005, between the Debenture Issuer
      and Wilmington Trust Company, not in its individual capacity but solely as
      trustee, and any indenture supplemental thereto pursuant to which the Debentures
      are to be issued to the Institutional Trustee of the Issuer.





“Liquidation
      Distribution” has the meaning set forth in the definition of “Guarantee
      Payments” herein.





“Majority
      in liquidation amount of the Capital Securities” means Holder(s) of outstanding
      Capital Securities, voting together as a class, but separately from the holders
      of Common Securities, of more than 50% of the aggregate liquidation amount
      (including the amount that would be paid upon the redemption, liquidation or
      otherwise on the date upon which the voting percentages are determined, plus
      unpaid Distributions accrued thereon to such date) of all Capital Securities
      then outstanding.





“Obligations”
      means any costs, expenses or liabilities (but not including liabilities related
      to taxes) of the Issuer, other than obligations of the Issuer to pay to holders
      of any Trust Securities the amounts due such holders pursuant to the terms
      of
      the Trust Securities.





“Officer’s
      Certificate” means, with respect to any Person, a certificate signed by one
      Authorized Officer of such Person. Any Officer’s Certificate delivered with
      respect to compliance with a condition or covenant provided for in this
      Guarantee shall include:





(a)  a
      statement that such officer signing the Officer’s 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 such officer in rendering the Officer’s Certificate;





(c)  a
      statement that 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





3


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





“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 within the
      Corporate Trust Office of the Guarantee Trustee with direct responsibility
      for
      the administration of any matters relating to this Guarantee, including any
      vice
      president, any assistant vice president, any secretary, any assistant secretary,
      the treasurer, any assistant treasurer, any trust officer or other officer
      of
      the Corporate Trust Office 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 corporate trust 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 3.1.





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





ARTICLE II





POWERS,
      DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEE





SECTION
      2.1  Powers
      and Duties of the Guarantee Trustee .





(a)  This
      Guarantee shall be held by the Guarantee Trustee for the benefit of the Holders
      of the Capital Securities, and the Guarantee Trustee shall not transfer this
      Guarantee to any Person except a Holder of Capital Securities exercising his
      or
      her rights pursuant to Section 4.4 (b) or to a Successor Guarantee Trustee
      on
      acceptance by such Successor Guarantee Trustee of its appointment to act as
      Successor Guarantee Trustee. The right, title and interest of the Guarantee
      Trustee shall automatically vest in any Successor Guarantee Trustee, and such
      vesting and cessation of title shall be effective whether or not conveyancing
      documents have been executed and delivered pursuant to the appointment of such
      Successor Guarantee Trustee.





(b)  If
      an
      Event of Default actually known to a Responsible Officer of the Guarantee
      Trustee has occurred and is continuing, the Guarantee Trustee shall enforce
      this
      Guarantee for the benefit of the Holders of the Capital Securities.





(c)  The
      Guarantee Trustee, before the occurrence of any Event of Default and after
      the
      curing or waiving of all Events of Default that may have occurred, shall
      undertake to perform only such duties as are specifically set forth in this
      Guarantee, and no implied covenants shall be read into this Guarantee against
      the Guarantee Trustee. In case an Event of Default has occurred (that has not
      been cured or waived pursuant to Section 2.4(b)) and is actually known to a
      Responsible Officer of the Guarantee Trustee, the Guarantee Trustee shall
      exercise such of the rights and powers vested in it by this Guarantee, and
      use
      the same degree of care and skill in its exercise thereof, as a prudent person
      would exercise or use under the circumstances in the conduct of his or her
      own
      affairs.





4


(d)  No
      provision of this Guarantee shall be construed to relieve the Guarantee Trustee
      from liability for its own negligent action, its own negligent failure to act,
      or its own willful misconduct or bad faith, except that:





(i)  prior
      to
      the occurrence of any Event of Default and after the curing or waiving of all
      Events of Default that may have occurred:





(A)  the
      duties and obligations of the Guarantee Trustee shall be determined solely
      by
      the express provisions of this Guarantee, and the Guarantee Trustee shall not
      be
      liable except for the performance of such duties and obligations as are
      specifically set forth in this Guarantee, and no implied covenants or
      obligations shall be read into this Guarantee against the Guarantee Trustee;
      and





(B)  in
      the
      absence of bad faith on the part of the Guarantee Trustee, the Guarantee Trustee
      may conclusively rely, as to the truth of the statements and the correctness
      of
      the opinions expressed therein, upon any certificates or opinions furnished
      to
      the Guarantee Trustee and conforming to the requirements of this Guarantee;
      but
      in the case of any such certificates or opinions furnished to the Guarantee
      Trustee, the Guarantee Trustee shall be under a duty to examine the same to
      determine whether or not on their face they conform to the requirements of
      this
      Guarantee;





(ii)  the
      Guarantee Trustee shall not be liable for any error of judgment made in good
      faith by a Responsible Officer of the Guarantee Trustee, unless it shall be
      proved that such Responsible Officer of the Guarantee Trustee or the Guarantee
      Trustee was negligent in ascertaining the pertinent facts upon which such
      judgment was made;





(iii)  the
      Guarantee Trustee shall not be liable with respect to any action taken or
      omitted to be taken by it in good faith in accordance with the written direction
      of the Holders of a Majority in liquidation amount of the Capital Securities
      relating to the time, method and place of conducting any proceeding for any
      remedy available to the Guarantee Trustee, or exercising any trust or power
      conferred upon the Guarantee Trustee under this Guarantee; and





(iv)  no
      provision of this Guarantee shall require the Guarantee Trustee to expend or
      risk its own funds or otherwise incur personal financial liability in the
      performance of any of its duties or in the exercise of any of its rights or
      powers, if the Guarantee Trustee shall have reasonable grounds for believing
      that the repayment of such funds is not reasonably assured to it under the
      terms
      of this Guarantee, or security and indemnity, reasonably satisfactory to the
      Guarantee Trustee, against such risk or liability is not reasonably assured
      to
      it.





5


SECTION
      2.2  Certain
      Rights of the Guarantee Trustee .





(a)  Subject
      to the provisions of Section 2.1:





(i)  The
      Guarantee Trustee may conclusively rely, and shall be fully protected in acting
      or refraining from acting upon, any resolution, certificate, statement,
      instrument, opinion, report, notice, request, direction, consent, order, bond,
      debenture, note, other evidence of indebtedness or other paper or document
      believed by it to be genuine and to have been signed, sent or presented by
      the
      proper party or parties.





(ii)  Any
      direction or act of the Guarantor contemplated by this Guarantee shall be
      sufficiently evidenced by an Officer’s Certificate.





(iii)  Whenever,
      in the administration of this Guarantee, the Guarantee Trustee shall deem it
      desirable that a matter be proved or established before taking, suffering or
      omitting any action hereunder, the Guarantee Trustee (unless other evidence
      is
      herein specifically prescribed) may, in the absence of bad faith on its part,
      request and conclusively rely upon an Officer’s Certificate of the Guarantor
      which, upon receipt of such request, shall be promptly delivered by the
      Guarantor.





(iv)  The
      Guarantee Trustee shall have no duty to see to any recording, filing or
      registration of any instrument or other writing (or any rerecording, refiling
      or
      reregistration thereof).





(v)  The
      Guarantee Trustee may consult with counsel of its selection, and the advice
      or
      opinion of such counsel with respect to legal matters shall be full and complete
      authorization and protection in respect of any action taken, suffered or omitted
      by it hereunder in good faith and in accordance with such advice or opinion.
      Such counsel may be counsel to the Guarantor or any of its Affiliates and may
      include any of its employees. The Guarantee Trustee shall have the right at
      any
      time to seek instructions concerning the administration of this Guarantee from
      any court of competent jurisdiction.





(vi)  The
      Guarantee Trustee shall be under no obligation to exercise any of the rights
      or
      powers vested in it by this Guarantee at the request or direction of any Holder,
      unless such Holder shall have provided to the Guarantee Trustee such security
      and indemnity, reasonably satisfactory to the Guarantee Trustee, against the
      costs, expenses (including attorneys’ fees and expenses and the expenses of the
      Guarantee Trustee’s agents, nominees or custodians) and liabilities that might
      be incurred by it in complying with such request or direction, including such
      reasonable advances as may be requested by the Guarantee Trustee; provided,
      however, that nothing contained in this Section 2.2(a)(vi) shall be taken to
      relieve the Guarantee Trustee, upon the occurrence of an Event of Default,
      of
      its obligation to exercise the rights and powers vested in it by this
      Guarantee.





(vii)  The
      Guarantee Trustee shall not be bound to make any investigation into the facts
      or
      matters stated in any resolution, certificate, statement, instrument, opinion,
      report, notice, request, direction, consent, order, bond, debenture, note,
      other
      evidence of indebtedness or other paper or document, but the Guarantee Trustee,
      in its discretion, may make such further inquiry or investigation into such
      facts or matters as it may see fit.





6


(viii)  The
      Guarantee Trustee may execute any of the trusts or powers hereunder or perform
      any duties hereunder either directly or by or through agents, nominees,
      custodians or attorneys, and the Guarantee Trustee shall not be responsible
      for
      any misconduct or negligence on the part of any agent or attorney appointed
      with
      due care by it hereunder.





(ix)  Any
      action taken by the Guarantee Trustee or its agents hereunder shall bind the
      Holders of the Capital Securities, and the signature of the Guarantee Trustee
      or
      its agents alone shall be sufficient and effective to perform any such action.
      No third party shall be required to inquire as to the authority of the Guarantee
      Trustee to so act or as to its compliance with any of the terms and provisions
      of this Guarantee, both of which shall be conclusively evidenced by the
      Guarantee Trustee’s or its agent’s taking such action.





(x)  Whenever
      in the administration of this Guarantee the Guarantee Trustee shall deem it
      desirable to receive instructions with respect to enforcing any remedy or right
      or taking any other action hereunder, the Guarantee Trustee (A) may request
      instructions from the Holders of a Majority in liquidation amount of the Capital
      Securities, (B) may refrain from enforcing such remedy or right or taking such
      other action until such instructions are received and (C) shall be protected
      in
      conclusively relying on or acting in accordance with such
      instructions.





(xi)  The
      Guarantee Trustee shall not be liable for any action taken, suffered, or omitted
      to be taken by it in good faith and reasonably believed by it to be authorized
      or within the discretion or rights or powers conferred upon it by this
      Guarantee.





(b)  No
      provision of this Guarantee shall be deemed to impose any duty or obligation
      on
      the Guarantee Trustee to perform any act or acts or exercise any right, power,
      duty or obligation conferred or imposed on it, in any jurisdiction in which
      it
      shall be illegal or in which the Guarantee Trustee shall be unqualified or
      incompetent in accordance with applicable law to perform any such act or acts
      or
      to exercise any such right, power, duty or obligation. No permissive power
      or
      authority available to the Guarantee Trustee shall be construed to be a
      duty.





SECTION
      2.3  Not
      Responsible for Recitals or Issuance of Guarantee .





The
      recitals contained in this Guarantee shall be taken as the statements of the
      Guarantor, and the Guarantee Trustee does not assume any responsibility for
      their correctness. The Guarantee Trustee makes no representation as to the
      validity or sufficiency of this Guarantee.





SECTION
      2.4  Events
      of Default; Waiver .





(a)  An
“Event
      of Default” under this Guarantee will occur upon the failure of the Guarantor to
      perform any of its payment or other obligations hereunder.





7


(b)  The
      Holders of a Majority in liquidation amount of the Capital Securities may,
      voting or consenting as a class, on behalf of the Holders of all of the Capital
      Securities, waive any past Event of Default and its consequences. Upon such
      waiver, any such Event of Default shall cease to exist, and shall be deemed
      to
      have been cured, for every purpose of this Guarantee, but no such waiver shall
      extend to any subsequent or other default or Event of Default or impair any
      right consequent thereon.





SECTION
      2.5  Events
      of Default, Notice .





(a)  The
      Guarantee Trustee shall, within 90 days after the occurrence of an Event of
      Default, transmit by mail, first class postage prepaid, to the Holders of the
      Capital Securities, notices of all Events of Default actually known to a
      Responsible Officer of the Guarantee Trustee, unless such defaults have been
      cured before the giving of such notice, provided, however, that the Guarantee
      Trustee shall be protected in withholding such notice if and so long as a
      Responsible Officer of the Guarantee Trustee in good faith determines that
      the
      withholding of such notice is in the interests of the Holders of the Capital
      Securities.





(b)  The
      Guarantee Trustee shall not be charged with knowledge of any Event of Default
      unless the Guarantee Trustee shall have received written notice thereof from
      the
      Guarantor or a Holder of the Capital Securities, or a Responsible Officer of
      the
      Guarantee Trustee charged with the administration of this Guarantee shall have
      actual knowledge thereof.





ARTICLE III





THE
      GUARANTEE TRUSTEE





SECTION
      3.1  The
      Guarantee Trustee. Eligibility .





(a)  There
      shall at all times be a Guarantee Trustee which shall:





(i)  not
      be an
      Affiliate of the Guarantor; and





(ii)  be
      a
      corporation or national association organized and doing business under the
      laws
      of the United States of America or any state thereof or of the District of
      Columbia, or Person authorized under such laws to exercise corporate trust
      powers, having a combined capital and surplus of at least 50 million U.S.
      dollars ($50,000,000), and subject to supervision or examination by federal,
      state or District of Columbia authority. If such corporation or national
      association publishes reports of condition at least annually, pursuant to law
      or
      to the requirements of the supervising or examining authority referred to above,
      then, for the purposes of this Section 3.1(a)(ii), the combined capital and
      surplus of such corporation or national association shall be deemed to be its
      combined capital and surplus as set forth in its most recent report of condition
      so published.





(b)  If
      at any
      time the Guarantee Trustee shall cease to be eligible to so act under Section
      3.1(a), the Guarantee Trustee shall immediately resign in the manner and with
      the effect set forth in Section 3.2(c).





8


(c)  If
      the
      Guarantee Trustee has or shall acquire any “conflicting interest” within the
      meaning of Section 310(b) of the Trust Indenture Act, the Guarantee Trustee
      shall either eliminate such interest or resign to the extent and in the manner
      provided by, and subject to, this Guarantee.





SECTION
      3.2  Appointment.
      Removal and Resignation of the Guarantee Trustee .





(a)  Subject
      to Section 3.2(b), the Guarantee Trustee may be appointed or removed without
      cause at any time by the Guarantor except during an Event of
      Default.





(b)  The
      Guarantee Trustee shall not be removed in accordance with Section 3.2(a) until
      a
      Successor Guarantee Trustee has been appointed and has accepted such appointment
      by written instrument executed by such Successor Guarantee Trustee and delivered
      to the Guarantor.





(c)  The
      Guarantee Trustee appointed to office shall hold office until a Successor
      Guarantee Trustee shall have been appointed or until its removal or resignation.
      The Guarantee Trustee may resign from office (without need for prior or
      subsequent accounting) by an instrument in writing executed by the Guarantee
      Trustee and delivered to the Guarantor, which resignation shall not take effect
      until a Successor Guarantee Trustee has been appointed and has accepted such
      appointment by an instrument in writing executed by such Successor Guarantee
      Trustee and delivered to the Guarantor and the resigning Guarantee
      Trustee.





(d)  If
      no
      Successor Guarantee Trustee shall have been appointed and accepted appointment
      as provided in this Section 3.2 within 60 days after delivery of an instrument
      of removal or resignation, the Guarantee Trustee resigning or being removed
      may
      petition any court of competent jurisdiction for appointment of a Successor
      Guarantee Trustee. Such court may thereupon, after prescribing such notice,
      if
      any, as it may deem proper, appoint a Successor Guarantee Trustee.





(e)  No
      Guarantee Trustee shall be liable for the acts or omissions to act of any
      Successor Guarantee Trustee.





(f)  Upon
      termination of this Guarantee or removal or resignation of the Guarantee Trustee
      pursuant to this Section 3.2, the Guarantor shall pay to the Guarantee Trustee
      all amounts owing to the Guarantee Trustee under Sections 7.2 and 7.3 accrued
      to
      the date of such termination, removal or resignation.





9


ARTICLE IV





GUARANTEE





SECTION
      4.1  Guarantee .





(a)  The
      Guarantor irrevocably and unconditionally agrees to pay in full to the Holders
      the Guarantee Payments (without duplication of amounts theretofore paid by
      the
      Issuer), as and when due, regardless of any defense (except defense of payment
      by the Issuer), right of set-off or counterclaim that the Issuer may have or
      assert. The Guarantor’s obligation to make a Guarantee Payment may be satisfied
      by direct payment of the required amounts by the Guarantor to the Holders or
      by
      causing the Issuer to pay such amounts to the Holders.





(b)  The
      Guarantor hereby also agrees to assume any and all Obligations of the Issuer
      and
      in the event any such Obligation is not so assumed, subject to the terms and
      conditions hereof, the Guarantor hereby irrevocably and unconditionally
      guarantees to each Beneficiary the full payment, when and as due, of any and
      all
      Obligations to such Beneficiaries. This Guarantee is intended to be for the
      Beneficiaries who have received notice hereof.





SECTION
      4.2  Waiver
      of Notice and Demand .





The
      Guarantor hereby waives notice of acceptance of this Guarantee and of any
      liability to which it applies or may apply, presentment, demand for payment,
      any
      right to require a proceeding first against the Issuer or any other Person
      before proceeding against the Guarantor, protest, notice of nonpayment, notice
      of dishonor, notice of redemption and all other notices and
      demands.





SECTION
      4.3  Obligations
      Not Affected .





The
      obligations, covenants, agreements and duties of the Guarantor under this
      Guarantee shall in no way be affected or impaired by reason of the happening
      from time to time of any of the following:





(a)  the
      release or waiver, by operation of law or otherwise, of the performance or
      observance by the Issuer of any express or implied agreement, covenant, term
      or
      condition relating to the Capital Securities to be performed or observed by
      the
      Issuer;





(b)  the
      extension of time for the payment by the Issuer of all or any portion of the
      Distributions, the price payable upon the redemption of the Capital Securities,
      the Liquidation Distribution or any other sums payable under the terms of the
      Capital Securities or the extension of time for the performance of any other
      obligation under, arising out of, or in connection with, the Capital Securities
      (other than an extension of time for the payment of the Distributions, the
      price
      payable upon the redemption of the Capital Securities, the Liquidation
      Distribution or other sums payable that results from the extension of any
      interest payment period on the Debentures);





10


(c)  any
      failure, omission, delay or lack of diligence on the part of the Holders to
      enforce, assert or exercise any right, privilege, power or remedy conferred
      on
      the Holders pursuant to the terms of the Capital Securities, or any action
      on
      the part of the Issuer granting indulgence or extension of any
      kind;





(d)  the
      voluntary or involuntary liquidation, dissolution, sale of any collateral,
      receivership, insolvency, bankruptcy, assignment for the benefit of creditors,
      reorganization, arrangement, composition or readjustment of debt of, or other
      similar proceedings affecting, the Issuer or any of the assets of the
      Issuer,





(e)  any
      invalidity of, or defect or deficiency in, the Capital Securities;





(f)  the
      settlement or compromise of any obligation guaranteed hereby or hereby incurred;
      or





(g)  any
      other
      circumstance whatsoever that might otherwise constitute a legal or equitable
      discharge or defense of a guarantor, it being the intent of this Section 4.3
      that the obligations of the Guarantor hereunder shall be absolute and
      unconditional under any and all circumstances.





There
      shall be no obligation of the Holders to give notice to, or obtain consent
      of,
      the Guarantor with respect to the happening of any of the
      foregoing.





SECTION
      4.4  Rights
      of Holders .





(a)  The
      Holders of a Majority in liquidation amount of the Capital Securities have
      the
      right to direct the time, method and place of conducting any proceeding for
      any
      remedy available to the Guarantee Trustee in respect of this Guarantee or to
      direct the exercise of any trust or power conferred upon the Guarantee Trustee
      under this Guarantee; provided, however, that (subject to Sections 2.1 and
      2.2)
      the Guarantee Trustee shall have the right to decline to follow any such
      direction if the Guarantee Trustee shall determine that the actions so directed
      would be unjustly prejudicial to the Holders not taking part in such direction
      or if the Guarantee Trustee being advised by legal counsel determines that
      the
      action or proceeding so directed may not lawfully be taken or if the Guarantee
      Trustee in good faith by its board of directors or trustees, executive committee
      or a trust committee of directors or trustees and/or Responsible Officers shall
      determine that the action or proceeding so directed would involve the Guarantee
      Trustee in personal liability.





(b)  Any
      Holder of Capital Securities may institute a legal proceeding directly against
      the Guarantor to enforce the Guarantee Trustee’s rights under this Guarantee,
      without first instituting a legal proceeding against the Issuer, the Guarantee
      Trustee or any other Person. The Guarantor waives any right or remedy to require
      that any such action be brought first against the Issuer, the Guarantee Trustee
      or any other Person before so proceeding directly against the
      Guarantor.





11


SECTION
      4.5  Guarantee
      of Payment .





This
      Guarantee creates a guarantee of payment and not of collection.





SECTION
      4.6  Subrogation .





The
      Guarantor shall be subrogated to all (if any) rights of the Holders of Capital
      Securities against the Issuer in respect of any amounts paid to such Holders
      by
      the Guarantor under this Guarantee; provided, however, that the Guarantor shall
      not (except to the extent required by applicable provisions of law) be entitled
      to enforce or exercise any right that it may acquire by way of subrogation
      or
      any indemnity, reimbursement or other agreement, in all cases as a result of
      payment under this Guarantee, if, after giving effect to any such payment,
      any
      amounts are due and unpaid under this Guarantee. If any amount shall be paid
      to
      the Guarantor in violation of the preceding sentence, the Guarantor agrees
      to
      hold such amount in trust for the Holders and to pay over such amount to the
      Holders.





SECTION
      4.7  Independent
      Obligations .





The
      Guarantor acknowledges that its obligations hereunder are independent of the
      obligations of the Issuer with respect to the Capital Securities and that the
      Guarantor shall be liable as principal and as debtor hereunder to make Guarantee
      Payments pursuant to the terms of this Guarantee notwithstanding the occurrence
      of any event referred to in subsections (a) through (g), inclusive, of Section
      4.3 hereof.





SECTION
      4.8  Enforcement .





A
      Beneficiary may enforce the Obligations of the Guarantor contained in Section
      4.1 (b) directly against the Guarantor, and the Guarantor waives any right
      or
      remedy to require that any action be brought against the Issuer or any other
      person or entity before proceeding against the Guarantor.





The
      Guarantor shall be subrogated to all rights (if any) of any Beneficiary against
      the Issuer in respect of any amounts paid to the Beneficiaries by the Guarantor
      under this Guarantee; provided, however, that the Guarantor shall not (except
      to
      the extent required by applicable provisions of law) be entitled to enforce
      or
      exercise any rights that it may acquire by way of subrogation or any indemnity,
      reimbursement or other agreement, in all cases as a result of payment under
      this
      Guarantee, if, after giving effect to such payment, any amounts are due and
      unpaid under this Guarantee. If any amount shall be paid to the Guarantor in
      violation of the preceding sentence, the Guarantor agrees to hold such amount
      in
      trust for the Beneficiaries and to pay over such amount to the
      Beneficiaries.





12


ARTICLE V





LIMITATION
      OF TRANSACTIONS; SUBORDINATION





SECTION
      5.1  Limitation
      of Transactions .





So
      long
      as any Capital Securities remain outstanding, if (a) there shall have occurred
      and be continuing an Event of Default or (b) Debenture Issuer shall have
      selected an Extension Period as provided in the Indenture and such period,
      or
      any extension thereof, shall have commenced and be continuing, then the
      Guarantor may not (x) declare or pay any dividends or distributions on, or
      redeem, purchase, acquire, or make a liquidation payment with respect to, any
      of
      the Guarantor’s capital stock, (y) make any payment of principal of or interest
      or premium, if any, on or repay, repurchase or redeem any debt securities of
      the
      Guarantor that rank in all respects *pari
      passu* with or
      junior in interest to the Debentures or (z) make any payment under any
      guarantees of the Guarantor that rank in all respects *pari
      passu* with or
      junior in interest to this Guarantee (other than (i) repurchases, redemptions
      or
      other acquisitions of shares of capital stock of the Guarantor (A) in connection
      with any employment contract, benefit plan or other similar arrangement with
      or
      for the benefit of one or more employees, officers, directors, or consultants,
      (B) in connection with a dividend reinvestment or stockholder stock purchase
      plan or (C) in connection with the issuance of capital stock of the Guarantor
      (or securities convertible into or exercisable for such capital stock), as
      consideration in an acquisition transaction entered into prior to the occurrence
      of the Event of Default or the applicable Extension Period, (ii) as a result
      of
      any exchange or conversion of any class or series of the Guarantor’s capital
      stock (or any capital stock of a subsidiary of the Guarantor) for any class
      or
      series of the Guarantor’s capital stock or of any class or series of the
      Guarantor’s indebtedness for any class or series of the Guarantor’s capital
      stock, (iii) the purchase of fractional interests in shares of the
      Guarantor’s capital stock pursuant to the conversion or exchange provisions of
      such capital stock or the security being converted or exchanged, (iv) any
      declaration of a dividend in connection with any stockholder’s rights plan, or
      the issuance of rights, stock or other property under any stockholder’s rights
      plan, or the redemption or repurchase of rights pursuant thereto, or (v) any
      dividend in the form of stock, warrants, options or other rights where the
      dividend stock or the stock issuable upon exercise of such warrants, options
      or
      other rights is the same stock as that on which the dividend is being paid
      or
      ranks *pari
      passu* with or
      junior in interest to such stock).





SECTION
      5.2  Ranking .





This
      Guarantee will constitute an unsecured obligation of the Guarantor and will
      rank
      subordinate and junior in right of payment to all present and future Senior
      Indebtedness (as defined in the Indenture) of the Guarantor. By their acceptance
      thereof, each Holder of Capital Securities agrees to the foregoing provisions
      of
      this Guarantee and the other terms set forth herein.





13


ARTICLE VI





TERMINATION





SECTION
      6.1  Termination .





This
      Guarantee shall terminate as to the Capital Securities (i) upon full payment
      of
      the price payable upon redemption of all Capital Securities then outstanding,
      (ii) upon the distribution of all of the Debentures to the Holders of all of
      the
      Capital Securities or (iii) upon full payment of the amounts payable in
      accordance with the Declaration upon dissolution of the Issuer. This Guarantee
      will continue to be effective or will be reinstated, as the case may be, if
      at
      any time any Holder of Capital Securities must restore payment of any sums
      paid
      under the Capital Securities or under this Guarantee.





ARTICLE VII





INDEMNIFICATION





SECTION
      7.1  Exculpation .





(a)  No
      Indemnified Person shall be liable, responsible or accountable in damages or
      otherwise to the Guarantor or any Covered Person for any loss, damage or claim
      incurred by reason of any act or omission of such Indemnified Person in good
      faith in accordance with this Guarantee and in a manner that such Indemnified
      Person reasonably believed to be within the scope of the authority conferred
      on
      such Indemnified Person by this Guarantee or by law, except that an Indemnified
      Person shall be liable for any such loss, damage or claim incurred by reason
      of
      such Indemnified Person’s negligence, willful misconduct or bad faith with
      respect to such acts or omissions.





(b)  An
      Indemnified Person shall be fully protected in relying in good faith upon the
      records of the Issuer or the Guarantor and upon such information, opinions,
      reports or statements presented to the Issuer or the Guarantor by any Person
      as
      to matters the Indemnified Person reasonably believes are within such other
      Person’s professional or expert competence and who, if selected by such
      Indemnified Person, has been selected with reasonable care by such Indemnified
      Person, including information, opinions, reports or statements as to the value
      and amount of the assets, liabilities, profits, losses, or any other facts
      pertinent to the existence and amount of assets from which Distributions to
      Holders of Capital Securities might properly be paid.





SECTION
      7.2  Indemnification .





(a)  The
      Guarantor agrees to indemnify each Indemnified Person for, and to hold each
      Indemnified Person harmless against, any and all loss, liability, damage, claim
      or expense incurred without negligence, willful ** misconduct
      or bad faith on the part of the Indemnified Person, arising out of or in
      connection with the acceptance or administration of the trust or trusts
      hereunder, including but not limited to the costs and expenses (including
      reasonable legal fees and expenses) of the Indemnified Person defending itself
      against, or investigating, any claim or liability in connection with the
      exercise or performance of any of the Indemnified Person’s powers or duties
      hereunder. The obligation to indemnify as set forth in this Section 7.2 shall
      survive the resignation or removal of the Guarantee Trustee and the termination
      of this Guarantee.





14


(b)  Promptly
      after receipt by an Indemnified Person under this Section 7.2 of notice of
      the
      commencement of any action, such Indemnified Person will, if a claim in respect
      thereof is to be made against the Guarantor under this Section 7.2, notify
      the
      Guarantor in writing of the commencement thereof, but the failure so to notify
      the Guarantor (i) will not relieve the Guarantor from liability under paragraph
      (a) above unless and to the extent that the Guarantor did not otherwise learn
      of
      such action and such failure results in the forfeiture by the Guarantor of
      substantial rights and defenses and (ii) will not, in any event, relieve the
      Guarantor from any obligations to any Indemnified Person other than the
      indemnification obligation provided in paragraph (a) above. The Guarantor shall
      be entitled to appoint counsel of the Guarantor’s choice at the Guarantor’s
      expense to represent the Indemnified Person in any action for which
      indemnification is sought (in which case the Guarantor shall not thereafter
      be
      responsible for the fees and expenses of any separate counsel retained by the
      Indemnified Person or Persons except as set forth below); provided, however,
      that such counsel shall be satisfactory to the Indemnified Person.
      Notwithstanding the Guarantor’s election to appoint counsel to represent the
      Indemnified Person in any action, the Indemnified Person shall have the right
      to
      employ separate counsel (including local counsel), and the Guarantor shall
      bear
      the reasonable fees, costs and expenses of such separate counsel, if (i) the
      use
      of counsel chosen by the Guarantor to represent the Indemnified Person would
      present such counsel with a conflict of interest, (ii) the actual or potential
      defendants in, or targets of, any such action include both the Indemnified
      Person and the Guarantor and the Indemnified Person shall have reasonably
      concluded that there may be legal defenses available to it and/or other
      Indemnified Persons which are different from or additional to those available
      to
      the Guarantor, (iii) the Guarantor shall not have employed counsel satisfactory
      to the Indemnified Person to represent the Indemnified Person within a
      reasonable time after notice of the institution of such action or (iv) the
      Guarantor shall authorize the Indemnified Person to employ separate counsel
      at
      the expense of the Guarantor. The Guarantor will not, without the prior written
      consent of the Indemnified Persons, settle or compromise or consent to the
      entry
      of any judgment with respect to any pending or threatened claim, action, suit
      or
      proceeding in respect of which indemnification or contribution may be sought
      hereunder (whether or not the Indemnified Persons are actual or potential
      parties to such claim or action) unless such settlement, compromise or consent
      includes an unconditional release of each Indemnified Person from all liability
      arising out of such claim, action, suit or proceeding.





SECTION
      7.3  Compensation;
      Reimbursement of Expenses .





The
      Guarantor agrees:





(a)  to
      pay to
      the Guarantee Trustee from time to time such compensation for all services
      rendered by it hereunder as the parties shall agree to from time to time (which
      compensation shall not be limited by any provision of law in regard to the
      compensation of a trustee of an express trust); and





15


(b)  except
      as
      otherwise expressly provided herein, to reimburse the Guarantee Trustee upon
      request for all reasonable expenses, disbursements and advances incurred or
      made
      by it in accordance with any provision of this Guarantee (including the
      reasonable compensation and the expenses and disbursements of its agents and
      counsel), except any such expense, disbursement or advance as may be
      attributable to the negligence, willful misconduct or bad faith of the Guarantee
      Trustee.





The
      provisions of this Section 7.3 shall survive the resignation or removal of
      the
      Guarantee Trustee and the termination of this Guarantee.





ARTICLE VIII





MISCELLANEOUS





SECTION
      8.1  Successors
      and Assigns .





All
      guarantees and agreements contained in this Guarantee shall bind the successors,
      assigns, receivers, trustees and representatives of the Guarantor and shall
      inure to the benefit of the Holders of the Capital Securities then outstanding.
      Except in connection with any merger or consolidation of the Guarantor with
      or
      into another entity or any sale, transfer or lease of the Guarantor’s assets to
      another entity, in each case to the extent permitted under the Indenture, the
      Guarantor may not assign its rights or delegate its obligations under this
      Guarantee without the prior approval of the Holders of a Majority in liquidation
      amount of the Capital Securities.





SECTION
      8.2  Amendments .





Except
      with respect to any changes that do not adversely affect the powers,
      preferences, rights or interests of Holders of the Capital Securities in any
      material respect (in which case no approval of Holders will be required), this
      Guarantee may be amended only with the prior approval of the Holders of a
      Majority in liquidation amount of the Capital Securities. The provisions of
      the
      Declaration with respect to amendments thereof shall apply equally with respect
      to amendments of the Guarantee.





SECTION
      8.3  Notices .





All
      notices provided for in this Guarantee shall be in writing, duly signed by
      the
      party giving such notice, and shall be delivered, telecopied or mailed by first
      class mail, as follows:





(a)  if
      given
      to the Guarantee Trustee, at the Guarantee Trustee’s mailing address set forth
      below (or such other address as the Guarantee Trustee may give notice of to
      the
      Holders of the Capital Securities): Wilmington Trust Company, Rodney Square
      North, 1100 North Market Street, Wilmington, Delaware 19890-0001, Attention:
      Corporate Capital Markets, Telecopy: 302-636-4140, Telephone:
      302-651-1000;





16


(b)  if
      given
      to the Guarantor, at the Guarantor’s mailing address set forth below (or such
      other address as the Guarantor may give notice of to the Holders of the Capital
      Securities and to the Guarantee Trustee): Bay National Corporation, 2328 West
      Joppa Road, Suite 325, Baltimore, Maryland 21093, Attention: Hugh W. Mohler,
      Telecopy: 410-494-2589, Telephone: 410-494-2580; or





(c)  if
      given
      to any Holder of the Capital Securities, at the address set forth on the books
      and records of the Issuer.





All
      such
      notices shall be deemed to have been given when received in person, telecopied
      with receipt confirmed, or mailed by first class mail, postage prepaid, except
      that if a notice or other document is refused delivery or cannot be delivered
      because of a changed address of which no notice was given, such notice or other
      document shall be deemed to have been delivered on the date of such refusal
      or
      inability to deliver.





SECTION
      8.4  Benefit .





This
      Guarantee is solely for the benefit of the Holders of the Capital Securities
      and, subject to Section 2.1(a), is not separately transferable from the Capital
      Securities.





SECTION
      8.5  Governing
      Law .





THIS
      GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS
      OF
      THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICT OF LAW PRINCIPLES OF SAID
      STATE OTHER THAN SECTION 5-1401 OF THE NEW YORK GENERAL OBLIGATIONS
      LAW.





SECTION
      8.6  Counterparts .





This
      Guarantee may contain more than one counterpart of the signature page and this
      Guarantee may be executed by the affixing of the signature of the Guarantor
      and
      the Guarantee Trustee to any of such counterpart signature pages. All of such
      counterpart signature pages shall be read as though one, and they shall have
      the
      same force and effect as though all of the signers had signed a single signature
      page.








17


THIS
      GUARANTEE is executed as of the day and year first above written.





BAY
      NATIONAL CORPORATION


As
      Guarantor








By: /s/
      Hugh W. Mohler


Name:
      Hugh W. Mohler


Title:
      President & Chair








WILMINGTON
      TRUST COMPANY,


As
      Guarantee Trustee








By: /s/
      Denise M. Geran


Name:
      Denise M. Geran


Title:
      Vice President