EXHIBIT 10.4
FIRST AMENDMENT TO
AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF
COLUMBIA BANKING SYSTEM, INC.
This First Amendment (this "Amendment") to the Amended and Restated Employee
Stock Purchase Plan of Columbia Banking System, Inc., is entered into by
Columbia Banking System, Inc., a Washington corporation (the "Company"), as of
September 26, 2018 (the "Effective Date").
Recitals
A.    The Company adopted the Amended and Restated Employee Stock Purchase Plan
of Columbia Banking System, Inc. (the "Plan") as of October 7, 2010.
B.    The Company desires to amend the Plan to allow employee participants, when
authorizing a payroll deduction under the Plan, to elect for the amount of the
deduction to be either a percentage of compensation or a flat dollar amount.
Amendment
In accordance with Section 12.5 of the Plan, the Plan is hereby amended as
follows:
1.Section 5.1 of the Plan is amended to read as follows:
"5.1    Amount of Deduction.
At the time a Participant files an authorization for payroll deduction, the
Participant shall elect to have deductions made from his Compensation on each
payday during the time he or she is a Participant in an Offering, and the
Participant shall elect the amount of the deduction as either (1) a percentage
of Compensation, in whole percentage increments, not to be less than 1% of
Compensation for the payroll date to which the deduction is applied, or (2) a
flat dollar amount per payroll date, which cannot be less than $15.00. A
Participant’s authorization will remain in effect for successive Offering
Periods unless terminated as provided in Section 5.3 of this Plan."
2.    All other provisions of the Plan remain in full force and effect, subject
only to the addition above.
This Amendment was executed as of the date first stated above, and was duly
adopted by the Personnel and Compensation Committee of the Board of Directors of
the Company as of September 26, 2018.
COLUMBIA BANKING SYSTEM, INC.

/s/ CATHLEEN DENT        
By: Cathleen Dent
Its: Assistant Corporate Secretary

603058-0002/4821-7695-2178.2