Filing Details

This Amendment No. 6 to Schedule 13D (Amendment No. 6) is being filed on behalf of SMC Select Co-Investment Fund I, LP, SMC Reserve Fund II, LP, SMC Reserve Fund II Offshore, LP, SMC Employees Partnership, SMC Select Co-Investment I GP, LLC, SMC Private Equity Holdings G.P., LLC, SMC Private Equity Holdings, LP, Spring Mountain Capital G.P., LLC, Spring Mountain Capital, LP, Spring Mountain Capital, LLC and Messrs. John L. Steffens and Gregory P. Ho and amends and supplements the Schedule 13D as originally filed with the Securities and Exchange Commission (the SEC) on May 10, 2012, as amended by Amendment No. 1 thereto, as filed with the SEC on April 12, 2013, and by Amendment No. 2 thereto, as filed with the SEC on January 8, 2015, as amended by Amendment No. 3 thereto, as filed with the SEC on September 4, 2015, and as amended by Amendment No. 4 thereto, as filed with the SEC on November 2, 2015, and as amended by Amendment No. 5 thereto, as filed with the SEC on January 27, 2016 (as amended, the Schedule 13D), with respect to shares of common stock, par value $0.01 per share (Common Stock) of American Power Group Corporation (the Company).

Unless otherwise indicated in this Amendment No. 6, each capitalized term used but not otherwise defined in this Amendment No. 6 shall have the meaning assigned to such term in the Schedule 13D.

The Agreement among the Reporting Persons to file jointly is attached as Exhibit 1 to the Schedule 13D. Each Reporting Person disclaims beneficial ownership of all shares of Common Stock, other than those reported herein as being beneficially owned by it.  The filing of this Amendment No. 6 represents the final amendment to the Schedule 13D and constitutes an exit filing for the Reporting Persons.

ITEM 5.

INTERESTS IN SECURITIES OF THE ISSUER

The information in Item 5 of the Schedule 13D is hereby amended and restated in its entirety as follows:

e)

On December 19, 2017, the Reporting Persons sold in a private transaction a sufficient number of securities so that the Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock.The filing of this Amendment No. 6 represents the final amendment to the Schedule 13D.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this amended statement on Schedule 13D is true, complete and correct.

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