SCHEDULE 13D

Explanatory Note

This Amendment No. 16 (this “Amendment No. 16”) relates to the Common Stock of A. M. Castle & Co., a Maryland corporation (the “Company”), which has its principal executive offices at 1420 Kensington Road, Suite 220, Oak Brook, Illinois.  This Amendment No. 16 is being filed in connection with that certain transaction pursuant to which a Reporting Person, W.B. & Co., purchased 4,630,795 shares of Common Stock owned by Raging Capital Master Fund, Ltd. (the “Transaction”). In addition, SGF, LLC, an Illinois limited liability company (“SGF”), a company affiliated with the Reporting Persons W.B. & Co. and FOM Corporation, entered into a commitment letter with the Company (the “Letter Agreement”) pursuant to which SGF agreed to provide a total of 15% of the principal of the Company’s new $100 million senior secured first lien term loan facility (the “Facility”). Except as otherwise set forth herein, this Amendment No. 16 does not modify any of the information previously reported by the Reporting Persons in the Schedule 13D as amended to date.

,

On November 2, 2016, SGF, a company affiliated with the Reporting Persons W.B. & Co. and FOM Corporation, entered into the Letter Agreement pursuant to which SGF agreed to provide a total of 15% of the principal of the Company’s new Facility subject to the satisfaction of certain conditions required by the Facility, including, but not limited to, the negotiation, execution and delivery of definitive documentation. The outstanding principal amount of the Facility and all accrued and unpaid interest thereon will be due and be payable on September 14, 2018.

Upon initial funding of the Facility, SGF will be issued warrants (the “Warrants”) to purchase an aggregate of 750,000 shares of the common stock of the Company. The Warrants will have exercise prices as follows: (a) 50% of the initially issued Warrants will have an exercise price of $0.50 per share and will expire 18 months from the date of grant and (ii) the remaining 50% of the Warrants will have an exercise price of $0.65 per share and will expire 18 months from the date of the grant.

On November 4, 2016, pursuant to the Purchase Agreement, W. B. & Co. purchased 4,630,795 shares of Common Stock of the Company held by Raging Capital Master Fund, Ltd. The aggregate purchase price of the 4,630,795 shares of Common Stock purchased by W. B. & Co. from Raging Capital Master Fund, Ltd. is $463,079.50. Immediately following the closing of the Transaction, W.B. & Co. transferred 100,000 shares of Common Stock to Mr. Mellin for no consideration.

The general partners of W. B. & Co. are Jonathan B. Mellin and Reuben S. Donnelley, who share voting power with respect to shares beneficially owned by W. B. & Co. Mr. Mellin serves as a director of the Company.

The foregoing descriptions of the terms of the Letter Agreement and the Purchase Agreement are not complete and are qualified in their entirety by reference to the text of the Letter Agreement and the Purchase Agreement, which are referenced as Exhibits 99.1 and 99.2, respectively, and incorporated herein by reference.

Item 7 is hereby amended to add the following exhibits:

99.1 Letter Agreement dated November 2, 2016, by and between W. B. & Co. and A. M. Castle & Co.
99.2 Purchase Agreement dated November 4, 2016, by and between W. B. & Co. and Raging Capital Master Fund, Ltd.

SIGNATURE

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.