<PAGE>

                                                                   EXHIBIT 10.13



                                LIFE INSURANCE

                     ENDORSEMENT METHOD SPLIT DOLLAR PLAN

                                   AGREEMENT


Insurer:                           Southland Life

Policy Number:                     0660000015

Bank:                              Community Trust Bank

Insured:                           Ronnie L. Austin

Relationship of Insured to Bank:   Executive


The respective rights and duties of the Bank and the Insured in the above-
referenced policy shall be pursuant to the terms set forth below:


I.   DEFINITIONS

     Refer to the policy contract for the definition of all terms in this
     Agreement.

II.  POLICY TITLE AND OWNERSHIP

     Title and ownership shall reside in the Bank for its use and for the use of
     the Insured all in accordance with this Agreement.  The Bank alone may, to
     the extent of its interest, exercise the right to borrow or withdraw on the
     policy cash values.  Where the Bank and the Insured (or assignee, with the
     consent of the Insured) mutually agree to exercise the right to increase
     the coverage under the subject Split Dollar policy, then, in such event,
     the rights, duties and benefits of the parties to such increased coverage
     shall continue to be subject to the terms of this Agreement.

III. BENEFICIARY DESIGNATION RIGHTS

     The Insured (or assignee) shall have the right and power to designate a
     beneficiary or beneficiaries to receive the Insured's share of the proceeds
     payable upon the death of the Insured, and to elect and change a payment
     option for such beneficiary, subject to any right or interest the Bank may
     have in such proceeds, as provided in this Agreement.
<PAGE>

IV.  PREMIUM PAYMENT METHOD

     The Bank shall pay an amount equal to the planned premiums and any other
     premium payments that might become necessary to keep the policy in force.

V.   TAXABLE BENEFIT

     Annually the Insured will receive a taxable benefit equal to the assumed
     cost of insurance as required by the Internal Revenue Service.  The Bank
     (or its administrator) will report to the Insured the amount of imputed
     income each year on Form W-2 or its equivalent.

VI.  DIVISION OF DEATH PROCEEDS

     Subject to Paragraphs VII and IX herein, the division of the death proceeds
     of the policy is as follows:

     A.   Should the Insured be employed by the Bank and die on or before the
          3rd day of January, 2002, the Insured's beneficiary(ies), designated
          in accordance with Paragraph III, shall be entitled to an amount equal
          to one hundred percent (100%) of the net at risk insurance portion of
          the proceeds.  The net at risk insurance portion is the total proceeds
          less the cash value of the policy.

     B.   Should the Insured be employed by the Bank and die subsequent to the
          3rd day of January, 2002, the Insured's beneficiary(ies), designated
          in accordance with Paragraph III, shall be entitled to an amount equal
          to eighty percent (80%) of the net at risk insurance portion of the
          proceeds.  The net at risk insurance portion is the total proceeds
          less the cash value of the policy.

     C.   Should the Insured not be employed by the Bank at the time of his or
          her death and die on or before the 3rd day of January, 2002, the
          Insured's beneficiary(ies), designated in accordance with Paragraph
          III, shall be entitled to the percentage as set forth hereinbelow of
          the proceeds described in Subparagraph VI (A) above that corresponds
          to the age of the Insured at the time that he terminated service with
          the Bank.  Should the Insured not be employed by the Bank at the time
          of his or her death and die subsequent to the 3rd day of January,
          2002, the Insured's beneficiary(ies) shall be entitled to the
          following percentage of the proceeds described in Subparagraph VI (B)
          hereinabove:


                                       2
<PAGE>

                                       Vested Percentage
               Age of Executive      (to a maximum of 100%)
               ----------------      ----------------------

               Age 56 or younger                 0%
               57                                14%
               58                                28%
               59                                42%
               60                                56%
               61                                70%
               62                                84%
               63                                90%
               64                                95%
               65 or older                      100%

      D.   The Bank shall be entitled to the remainder of such proceeds.

      E.   The Bank and the Insured (or assignees) shall share in any interest
           due on the death proceeds on a pro rata basis as the proceeds due
           each respectively bears to the total proceeds, excluding any such
           interest.

VII.  DIVISION OF THE CASH SURRENDER VALUE OF THE POLICY

      The Bank shall at all times be entitled to an amount equal to the policy's
      cash value, as that term is defined in the policy contract, less any
      policy loans and unpaid interest or cash withdrawals previously incurred
      by the Bank and any applicable surrender charges. Such cash value shall be
      determined as of the date of surrender or death as the case may be.

VIII. RIGHTS OF PARTIES WHERE POLICY ENDOWMENT OR ANNUITY ELECTION EXISTS

      In the event the policy involves an endowment or annuity element, the
      Bank's right and interest in any endowment proceeds or annuity benefits,
      on expiration of the deferment period, shall be determined under the
      provisions of this Agreement by regarding such endowment proceeds or the
      commuted value of such annuity benefits as the policy's cash value. Such
      endowment proceeds or annuity benefits shall be considered to be like
      death proceeds for the purposes of division under this Agreement.

IX.   TERMINATION OF AGREEMENT

      This Agreement shall terminate upon the occurrence of any one of the
      following:


                                       3
<PAGE>

     1.   The Insured shall terminate service with the Bank prior to attaining
          age fifty-seven (57); or

     2.   The Insured shall breach any provision of the Employment Agreement
                                                        --------------------
          between Ronnie Austin and Community Trust Financial Services
          Corporation dated January 1, 1998 (hereinafter referred to as the,
          "Executive's Employment Agreement"); or

     3.   The Insured shall be discharged from employment with the Bank for
          cause.  The term for "cause" shall be as defined in subparagraph 10.01
          (c), "Grounds for Termination", of the Executive's Employment
                -----------------------
          Agreement; or

     4.   Surrender, lapse, or other termination of the Policy by the Bank.

     Upon such termination, the Insured (or assignee) shall have a fifteen (15)
     day option to receive from the Bank an absolute assignment of the policy in
     consideration of a cash payment to the Bank, whereupon this Agreement shall
     terminate.  Such cash payment referred to hereinabove shall be the greater
     of:

     1.  The Bank's share of the cash value of the policy on the date of such
         assignment, as defined in this Agreement; or

     2.  The amount of the premiums which have been paid by the Bank prior to
         the date of such assignment.

     If, within said fifteen (15) day period, the Insured fails to exercise said
     option, fails to procure the entire aforestated cash payment, or dies, then
     the option shall terminate, and the Insured (or assignee) agrees that all
     of the Insured's rights, interest and claims in the policy shall terminate
     as of the date of the termination of this Agreement.

     The Insured expressly agrees that this Agreement shall constitute
     sufficient written notice to the Insured of the Insured's option to receive
     an absolute assignment of the policy as set forth herein.

     Except as provided above, this Agreement shall terminate upon distribution
     of the death benefit proceeds in accordance with Paragraph VI above.

X.   INSURED'S OR ASSIGNEE'S ASSIGNMENT RIGHTS

     The Insured may not, without the written consent of the Bank, assign to any
     individual, trust or other organization, any right, title or interest in
     the subject policy nor any rights, options, privileges or duties created
     under this Agreement.

                                       4
<PAGE>

XI.   AGREEMENT BINDING UPON THE PARTIES

      This Agreement shall bind the Insured and the Bank, their heirs,
      successors, personal representatives and assigns.

XII.  ERISA PROVISIONS

      The following provisions are part of this Agreement and are intended to
      meet the requirements of the Employee Retirement Income Security Act of
      1974 ("ERISA"):

      A.  Named Fiduciary and Plan Administrator.
          ---------------------------------------

      The "Named Fiduciary and Plan Administrator" of this Endorsement Method
      Split Dollar Agreement shall be Community Trust Bank until resignation or
      removal by the Board of Directors. As Named Fiduciary and Plan
      Administrator, the Bank shall be responsible for the management, control,
      and administration of this Split Dollar Plan as established herein. The
      Named Fiduciary may delegate to others certain aspects of the management
      and operation responsibilities of the Plan, including the employment of
      advisors and the delegation of any ministerial duties to qualified
      individuals.

      B.  Funding Policy.
          --------------

      The funding policy for this Split Dollar Plan shall be to maintain the
      subject policy in force by paying, when due, all premiums required.

      C.  Basis of Payment of Benefits.
          ----------------------------

      Direct payment by the Insurer is the basis of payment of benefits under
      this Agreement, with those benefits in turn being based on the payment of
      premiums as provided in this Agreement.

      D.  Claim Procedures.
          ----------------

      Claim forms or claim information as to the subject policy can be obtained
      by contacting The Benefit Marketing Group, Inc. (770-952-1529). When the
      Named Fiduciary has a claim which may be covered under the provisions
      described in the insurance policy, they should contact the office named
      above, and they will either complete a claim form and forward it to an
      authorized representative of the Insurer or advise the named Fiduciary
      what further requirements are necessary. The Insurer will evaluate and
      make a decision as to payment. If the claim is payable, a benefit check
      will be issued in accordance with the terms of this Agreement.

                                       5
<PAGE>

      In the event that a claim is not eligible under the policy, the Insurer
      will notify the Named Fiduciary of the denial pursuant to the requirements
      under the terms of the policy. If the Named Fiduciary is dissatisfied with
      the denial of the claim and wishes to contest such claim denial, they
      should contact the office named above and they will assist in making
      inquiry to the Insurer. All objections to the Insurer's actions should be
      in writing and submitted to the office named above for transmittal to the
      Insurer.

XIII. GENDER

      Whenever in this Agreement words are used in the masculine or neuter
      gender, they shall be read and construed as in the masculine, feminine or
      neuter gender, whenever they should so apply.

XIV.  INSURANCE COMPANY NOT A PARTY TO THIS AGREEMENT

      The Insurer shall not be deemed a party to this Agreement, but will
      respect the rights of the parties as herein developed upon receiving an
      executed copy of this Agreement. Payment or other performance in
      accordance with the policy provisions shall fully discharge the Insurer
      for any and all liability.

XV.   CHANGE OF CONTROL

      Change of Control shall be as defined in paragraph 10.03, ""Change in
                                                                 ----------
      Control" Defined", of the Executive's Employment Agreement.  Upon a Change
      ----------------
      of Control, if the Insured's employment is subsequently terminated, except
      for cause, then the Insured shall be one hundred percent (100%) vested in
      the benefits promised in this Agreement and, therefore, upon the death of
      the Insured, the Insured's beneficiary(ies) (designated in accordance with
      Paragraph III) shall receive the death benefit provided herein as if the
      Insured had died while employed by the Bank [See Subparagraphs VI (A) &
      (B)].

XVI.  AMENDMENT OR REVOCATION

      It is agreed by and between the parties hereto that, during the lifetime
      of the Insured, this Agreement may be amended or revoked at any time or
      times, in whole or in part, by the mutual written consent of the Insured
      and the Bank.

XVII. EFFECTIVE DATE

      The Effective Date of this Agreement shall be January 3, 2000.

XVIII. SEVERABILITY AND INTERPRETATION

                                       6
<PAGE>

     If a provision of this Agreement is held to be invalid or unenforceable,
     the remaining provisions shall nonetheless be enforceable according to
     their terms.  Further, in the event that any provision is held to be over
     broad as written, such provision shall be deemed amended to narrow its
     application to the extent necessary to make the provision enforceable
     according to law and enforced as amended.

XIX. APPLICABLE LAW

     The validity and interpretation of this Agreement shall be governed by the
     laws of the State of Georgia.


Executed at Hiram, Georgia this 13th day of January, 2000.


                                    COMMUNITY TRUST BANK
                                    Hiram, Georgia


/s/ Angel Byrd                    By:    /s/ William A. Foster, III
------------------------------        -----------------------------------------
Witness - Angel Byrd                  William A. Foster, III - Chairman


/s/ T. E. Durham, Jr.                    /s/ Ronnie L. Austin
------------------------------        -----------------------------------------
Witness - T. E. Durham, Jr.           Ronnie L. Austin

                                       7