June 1, 2013 Campbell & Company, Inc.

Exhibit 10.5(c)

June 1, 2013

Xxxxxxxx & Company, Inc.

0000 Xxxxxx Xxxx Xxxxx

Baltimore, MD 21209

Attn: Mr. Xxx Xxxxx

Re: Management Agreement Renewals

Dear Xx. Xxxxx:

We are writing with respect to your management agreements concerning the commodity pools to which reference is made below (the “Management Agreements”). We are extending the term of the Management Agreements through June 30, 2014 and all other provisions of the Management Agreements will remain unchanged.

• Potomac Futures Fund L.P.

• CMF Xxxxxxxx Master Fund L.P.

Please acknowledge receipt of this modification by signing one copy of this letter and returning it to the attention of Xx. Xxxxxx Xxxxxx at the address above or fax to 000-000-0000. If you have any questions I can be reached at 000-000-0000.

Very truly yours,
CERES MANAGED FUTURES LLC
By:		/s/ Xxxxxx Xxxxxx
		Xxxxxx Xxxxxx
		Chief Financial Officer & Director
XXXXXXXX & COMPANY, INC.
By:		/s/ Xxxxxx X. Xxxxx

Print Name: Xxxxxx X. Xxxxx

XX/sr