13D Filing: Southeastern Asset Management and Sonic Corp (SONC)

Signatures

After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Dated: April 4, 2018

SOUTHEASTERN ASSET MANAGEMENT, INC.

By /s/ Andrew R. McCarroll
_______________________________
Andrew R. McCarroll
General Counsel

LONGLEAF PARTNERS SMALL-CAP FUND
By: Southeastern Asset Management, Inc.

By /s/ Andrew R. McCarroll
_______________________________
Andrew R. McCarroll
General Counsel

O. MASON HAWKINS
(Individually)

/s/ O. Mason Hawkins
_______________________________

Joint Filing Agreement

In accordance with Rule 13d-1(k) under the Securities Exchange Act
of 1934, the persons or entities named below agree to the joint
filing on behalf of each of them of this Schedule 13G with respect
to the Securities of the Issuer and further agree that this joint
filing agreement be included as an exhibit to this Schedule 13G. In
evidence thereof, the undersigned hereby execute this Agreement as
of April 4, 2018.

Southeastern Asset Management, Inc.

By /s/ Andrew R. McCarroll
__________________________________
Andrew R. McCarroll
Vice President and General Counsel

Longleaf Partners Small-Cap Fund

By: Southeastern Asset Management, Inc.

By /s/ Andrew R. McCarroll
_______________________________
Andrew R. McCarroll
Vice President & General Counsel

O. Mason Hawkins, Individually

/s/ O. Mason Hawkins
_______________________________