13D Filing: Highbridge Capital Management and Castle AM & Co (CASLQ)

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Exhibit 1

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the
foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement
on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements.
The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and
accuracy of the information concerning him or it contained herein and therein, but shall not be responsible for the completeness
and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such
information is inaccurate.

Date: September 11, 2017

HIGHBRIDGE CAPITAL MANAGEMENT, LLC
By: /s/ John Oliva
Name: John Oliva
Title: Managing Director
1992 MSF INTERNATIONAL LTD.
By: Highbridge Capital Management, LLC,
solely in its capacity as its Trading Manager
By: /s/ John Oliva
Name: John Oliva
Title: Managing Director

Follow A. M. Castle & Co. (NYSE:CTAM)

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