1

                                  EXHIBIT 4.3

                            ENTERBANK HOLDINGS, INC.
                          INCENTIVE STOCK OPTION PLAN
                          ---------------------------

                                     1.

      This Incentive Stock Option Plan for ENTERBANK HOLDINGS, INC. is
intended to advance the interests of the Organization by providing Key
Employees who have substantial responsibility for the direction and management
of the Company and its Subsidiaries with additional incentive to promote the
success of the Organization's business, and by encouraging the Key Employees
to remain in the employ of the Organization. The above aims will be
accomplished through the granting of certain stock options. It is intended
that options issued under the Plan qualify as ISOs, and the provisions of the
Plan shall be interpreted in accordance with this intention.

                                      2.

      The items defined below shall have the following meanings throughout
the Plan:

      2.1   "Bank" means ENTERPRISE BANK, a Missouri financial institution.

      2.2   "Board" means the Board of Directors of Company.

      2.3   "Code" means the Internal Revenue Code of 1986, as amended.

      2.4   "Company" means ENTERBANK HOLDINGS, INC., a Delaware corporation.

      2.5   "ISOs" means stock options which qualify as incentive stock
options under Section 422 of the Code.

      2.6   "Key Employees" means officers, directors, executives and
supervisory personnel, as well as other employees of the Company or the
Subsidiaries, who have substantial responsibility for the direction and
management of the Organization.

      2.7   "Organization" means the Company, the Bank and the Subsidiaries.

      2.8   "Optionee" means the person to whom an option is granted.

      2.9   "Plan" means the Incentive Stock Option Plan as defined by the
provisions hereof.

      2.10  "Stock" means the voting common stock of Company.

 2

      2.11  "Subsidiaries" means any subsidiary bank or corporation owned or
controlled by the Company, the Bank, or one of the Subsidiaries.

      2.12  "Ten Percent Shareholder" means any individual who at the time
an option is granted owns directly or indirectly stock possessing more than
10% of the total combined voting power of all classes of stock of the Company,
taking into account the provisions of Section 424(d) of the Code.

                                       3.

      The Board shall administer the Plan. Subject to the provisions of the
Plan, the Board shall have authority, in its sole and absolute discretion:
(a) to determine the employees of the Organization (from among the class of
employees eligible under Section 4 to receive options under the Plan) to
whom options shall be granted; (b) to determine the time or times at which
options shall be granted; (c) to determine the option price of the shares
subject to each option, which price shall not be less than the minimum
specified in Section 6.1; (d) to determine (subject to Section 6.2) the
duration of the exercise period for each option; (e) to determine the form
of options granted hereunder; (f) to determine the exact provisions of any
ISO issued hereunder so long as such provisions are not inconsistent with
Section 422 of the Code; and (g) to interpret the Plan and to prescribe,
amend, and rescind rules and regulations relating to it. For purposes of
acting with respect to the Plan, a majority of the members of the Board
shall constitute a quorum and the acts of a majority of the members present
at any meeting at which a quorum is present, or acts approved in writing by
a majority of the members of the Board, shall be deemed the acts of the Board.

                                       4.

      4.1   Options shall be granted only to Key Employees.

      4.2   The aggregate fair market value (determined at the time the option
is granted) of the Stock with respect to which ISOs are exercisable for the
first time by an individual during any calendar year (under this Plan or any
other ISO plan of Company) shall not exceed $100,000.

                                       5.

      5.1   The maximum number of shares of Stock which may be issued pursuant
to ISOs granted hereunder (subject to adjustment as provided in Section 5.3
hereof) shall be 144,000 shares and, to the extent allowed by law, said
number of shares will be reserved for use upon the exercise of options which
may be granted at any time and from time to time under the Plan (subject to
the provisions of Section 10). These shares may be

                                       2
 3

in whole or in part, as the Board shall from time to time determine, authorized
but unissued shares or unauthorized shares which may be authorized pursuant to
powers of attorney granted by shareholders of the Company. Any shares subject
to an option under the Plan, which option for any reason expires or is
terminated unexercised as to such shares, may again be subjected to an
option under the Plan.

      5.2   In the event that additional shares of Stock are issued pursuant
to a stock split or a stock dividend, the number of shares of Stock then
covered by each outstanding option granted hereunder shall be increased
proportionally and the per share price of such shares shall be decreased
proportionally with no change in the total purchase price of the shares
then so covered. The number of shares of Stock reserved for the purpose
of the Plan shall also be increased proportionally. In the event that the
shares of Stock of the Company from time to time issued and outstanding are
reduced by a combination of shares, the number of shares of Stock then
covered by each outstanding option granted hereunder shall be reduced
proportionally and the per share price shall be increased proportionally
with no change in the total price of the shares then so covered. The number
of shares of Stock reserved for the purposes of the Plan shall also be
reduced proportionally. No fractional shares shall be issued, and any
fractional shares resulting from the computations pursuant to this Section
5.2 shall be eliminated from the respective option. No adjustment shall be
made for dividends (other than stock dividends) or the issuance to stockholders
of rights to subscribe for additional common stock or other securities.

                                       6.

      6.1   The option price for each share of Stock covered by an ISO shall
be an amount not less than 100% (or, in the case of an ISO granted to a Ten
Percent Shareholder, not less than 110%) of the fair market value of the
Stock on the date the option is granted.

      6.2   All ISOs issued under the Plan shall be for such period as the
Board shall determine, but for not more than ten (10) years (or, if the
Optionee is a Ten Percent Shareholder, five (5) years) from the date of
grant thereof.

      6.3   The period of the ISO, once it is granted, may be reduced only
as provided for in Section 7 in connection with the termination of employment
of the Optionee.

      6.4   Except as provided in Section 7 hereof, no ISO may be exercised
unless the Optionee is at the time of such exercise in the employ of the
Organization and shall have been continuously so employed since the grant
of the option.

                                    3
 4

      6.5   Each option granted under the Plan shall be non-transferable and
shall be exercisable only by the Optionee to whom the option is granted. No
option granted under the Plan or any of the rights and privileges thereby
conferred shall be transferred, assigned, pledged, or hypothecated in any
way (whether by operation of law or otherwise), and no such option, right,
or privilege shall be subject to execution, attachment, or similar process.
Upon any attempt to so transfer, assign, pledge, hypothecate, or otherwise
dispose of the option or of any right or privilege conferred thereby, contrary
to the provisions hereof, or upon the levy of any attachment or similar
process upon such option, right or privilege, the option and such rights
and privileges shall immediately become null and void.

                                       7.

      7.1   In the event of an Optionee's termination of employment for any
reason, such Optionee or the Optionee's guardian or personal representative
may exercise any Options theretofore granted, which have vested and are not
then expired, within three (3) months after such termination of employment;
provided, however, in the case of termination of employment due to permanent
disability, the three month period of exercise shall be extended to one year.

      7.2   The transfer of a Key Employee from the Company and any Subsidiary
to the Company or any Subsidiary shall not be considered an interruption or
termination of employment for purposes of this Agreement.

                                       8.

      8.1   The exercise of any ISO shall also be contingent upon receipt
by the Company of cash or cashier's check to its order, in an amount equal
to the full option price of the shares being purchased.

      8.2   No Optionee or his or her legal representative, heir, or legatee,
as the case may be, will be, or will be deemed to be, a holder of any share
subject to an option unless and until appropriate documents evidencing such
shares are issued under the provisions of the Plan. Adjustment shall be made,
however, for dividends for which the record date is after the date the option
is exercised but prior to the date such evidence of such shares is issued.

      8.3   Each option shall be subject to the condition that if at any time
the Board shall determine, in its discretion, that the listing, registration,
or qualification of the shares covered thereby upon any securities exchange
or under any state or federal law or that the consent or approval of any
governmental regulatory body is necessary or desirable as a condition

                                    4
 5

of, or in connection with, the issue or purchase of shares under such option,
such shares will not be issued unless and until such listing, registration,
qualification, consent, or approval shall have been effected or obtained free
of any conditions not acceptable to the Board.

      8.4   Neither the Plan nor any option agreement covering options
issued under the Plan is to be construed as a contract of employment of any
kind whatsoever between a Key Employee and any present or future employer
of a Key Employee.

      8.5   Exercise of an option shall result in a decrease in the number
of shares of Stock which thereafter may be available under the Plan by the
number of shares as to which the option is exercised.

                                       9.

      No option shall be granted pursuant to the Plan after ten (10) years
from the date the Plan is adopted by the Board, or the date the Plan is
approved by the majority of the outstanding shares of each class of Company
stock, whichever is earlier.

                                       10.

      The Board may at any time terminate the Plan, and at any time and
from time to time modify and amend the Plan in any respect; provided, however,
that no such amendment shall: (a) increase (except in accordance with Section
5.2) the maximum number of shares for which options may be granted under the
Plan either in the aggregate or to any individual Optionee; or (b) reduce
(except in accordance with Section 5.2) the minimum option prices which may
be established under the Plan; or (c) extend the maximum periods provided
for in Sections 6.2 and 10, respectively, during which options may be
exercised or granted; or (d) change the provisions relating to the determination
of employees to whom options shall be granted and the number of shares to be
covered by such options; or (e) change the provisions relating to adjustments
to be made upon changes in capitalization. The termination or any modification
or amendment of the Plan shall not, without the consent of an Optionee, affect
his or her rights under an option theretofore granted to such Optionee.

                                       11.

      The Plan shall not affect the provisions of any non-qualified stock
options granted to any employee of the Organization under any other plan
relating to non-qualified stock options; nor shall it affect any of the
rights of any employee or the Organization to whom such a non-qualified
stock option was granted.

                                    5
 6

                                       12.

      This Plan shall become effective on the later of the date of its
adoption by the Board or its approval by the vote of the holders of a
majority of the outstanding shares of each class of the Company's stock.
This Plan shall not become effective unless such shareholder approval shall
be obtained within twelve (12) months before or after the adoption of the
Plan by the Board.

                                       13.

      In the event the Company shall assume the liability of any incentive
stock option plan of the Bank or any of the Subsidiaries, the Board may apply
such liability to this Plan and may further adjust the number of shares and
option prices of the options of the prior plan proportionately so that an
equitable transfer and assumption of liability may be accomplished.


                                    6