Item 1.

Security and Issuer

The title and class of equity security to which this statement relates is the Common Stock, par value $0.01 per share (the “Common Stock”), of Core-Mark Holding Company, Inc. The address of the Issuer’s principal executive offices is 395 Oyster Point Boulevard, Suite 415, South San Francisco, California 94080.

Item 2.

Identity and Background

All entities referenced herein are located at 61 Broadway, New York, New York 10006 and are investment partnerships or investment advisors. Loeb Arbitrage Fund (“LAF”) is a New York limited partnership. Its general partner is Loeb Arbitrage Management, LLC (“LAM”), a Delaware corporation. Loeb Arbitrage B Fund LP (“LAFB”), is a Delaware limited partnership. Its investment manager is LAM. The President of these general partners is Gideon J. King. The other officers of LAM include Thomas L. Kempner, Chairman of the Board; Michael S. Emanuel, Vice President and Secretary; Peter A. Tcherepnine, Vice President and Edward J. Campbell, Vice President. Loeb Partners Corporation (“LPC”), is a Delaware corporation. It is a registered broker/dealer and a registered investment adviser. Thomas L. Kempner is its President, Chief Executive Officer and a director. Gideon J. King is Executive Vice President. The other officers listed above are also officers of LPC. Loeb Holding Corporation (“LHC”), a Maryland corporation, is the sole stockholder of LAM and LPC. Thomas L. Kempner is its President and a director as well as its Chief Executive Officer and majority stockholder. Bruce L. Lev, Norman N. Mintz and Peter A. Tcherepnine are also directors. Loeb Offshore Fund, Ltd. (“LOF”) and Loeb Offshore B Fund Ltd. (“LOFB”), are each a Cayman Islands exempted company. Loeb Offshore Management, LLC (“LOM”) is a Delaware limited liability company, a registered investment adviser and is wholly owned by Loeb Holding Corporation. It is the investment adviser of LOF and LOFB. Gideon J. King and Thomas L. Kempner are Directors of LOF and LOFB and Managers of LOM. Loeb Marathon Fund, LP (“LMF”) is a Delaware limited partnership whose general partner is LAM. Loeb Marathon Offshore Fund Ltd. (“LMOF”), is a Cayman Islands exempted company. LOM is the investment adviser of LMOF. All of the individuals named in this Item 2 are United States citizens. None of the entities or individuals named in this Item 2 have been, within the last five years, convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding been or are subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violations with respect to such laws.

Item 3.

Source and Amount of Funds or Other Compensation

Shares of Common Stock were acquired by LAF, LPC**, LOF, LMF, LMOF, LAFB and LOFB (“Loeb”) in margin accounts maintained with Bear Stearns Securities Corp.

Item 4.

Purpose of Transaction