Exhibit 10.1

MEMO OF UNDERSTANDING

The purpose of this memorandum is to outline the basis of the work and
compensation that will be performed by Lawrence A. Collett (Chairman) after he
retires as Chief Executive Officer and assumes the role of Chairman of the Board
of, and consultant to, Cass Information Systems, Inc.

 

  I. Role and Responsibilities

The Chairman’s duties shall be as set forth in the description attached to this
memorandum.

 

  II. Time Commitments

It is expected that the Chairman will spend not more than one day per week
engaged in the above duties or activities as requested by the Company.

This new position will begin July 20, 2008.

It is understood that this position will be for an initial three-year period,
but can be extended upon the mutual agreement of the Chairman and the Board of
Directors. It is recognized this understanding can be terminated at any time by
either party.

 

  III. Compensation

 

  A. Annual Fee – For serving in the outlined capacity, the Chairman shall
receive a fee of $150,000 per year, paid monthly.

 

  B. The Chairman shall also receive the annual stock compensation and the
monthly Board of Directors retainer and monthly meeting fees. In addition he
will receive fees for each loan committee meeting he attends as a member of that
committee. He shall not receive a fee as an ex-officio member of other board
committees.

 

  C. He will be reimbursed for business-related expenses including but not
limited to, country club membership and automobile expenses at a level
equivalent to that provided during employment, and membership dues for
organizations such as the Regional Business Council and CEO Council which, in
the Board’s opinion, are beneficial for the Company.

 

  IV. Other Compensation Issues

 

  A. He will not participate in the Profit Sharing Plan of the Company after
6/30/2008.

 

  B. He will retain full interest in the stock bonus awards and stock option
awards that have been provided up to the time of his retirement. These will be
allowed to vest according to the original schedule and terms of the individual
agreements with respect to all matters other than the terms of the individual
agreements relating to the termination of Mr. Collett’s employment.

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  V. Future Contingencies

 

  A. The annual fee, board fees and board stock compensation shall cease in the
event of the Chairman’s death.

 

  B. In the event of disability, all payments would continue until the Board of
Directors determined that the Chairman could not serve as originally planned for
the duration of the term.

 

Cass Information Systems, Inc.

    By:  

/s/ Eric H. Brunngraber

   

/s/ Lawrence A. Collett

Name:   Eric H. Brunngraber     Lawrence A. Collett Title:   President and Chief
Operating Officer