SECURITIES AND EXCHANGE COMMISSION
 
WASHINGTON, D. C. 20549
 
SCHEDULE 13G/A
(Rule 13-d-102)

(Amendment No. 1)
 
Core-Mark Holding Company, Inc.
(Name of Issuer)
 
Common Stock, $.01 Par Value Per Share
(Title of Class of Securities)
 
218681104
 (CUSIP Number of Class of Securities)
 
December 31, 2009
 (Date of Event which Requires Filing of this Statement)
 
This filing reflects the reporting persons’ passive investor status and converts their filing from prior Schedule 13D (and amendments) filings to this Schedule 13G filing.
 
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
 
o  RULE 13d-1(b)
x  RULE 13d-1(c)
o  RULE 13d-1(d)

 
 
 

CUSIP NO.  218681104
 
1) Name of Reporting Person
   
Wynnefield Partners Small Cap Value, L.P.
 
2) Check The Appropriate Box If A Member Of A Group (See Instructions)
   (a)
   (b)x Reporting person is affiliated with other persons
 
3) SEC Use Only
   
4) Citizenship Or Place Of Organization:  Delaware
      
NUMBER OF SHARES
5) Sole Voting Power:
BENEFICIALLY OWNED
214,808 Shares
BY EACH REPORTING
    
PERSON WITH
6) Shared Voting Power
 
0
 
       
 
7) Sole Dispositive Power:
 
214,808 Shares
 
   
 
8) Shared Dispositive Power
 
0
   
9)  Aggregate Amount Beneficially Owned By Each Reporting Person:
214,808 Shares
 
10) Check Box If The Aggregate Amount In Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
2.1%
 
12) Type of Reporting Person (See Instructions) PN
 
 
 
1
 

CUSIP NO. 218681104
 
1) Name of Reporting Person
 
Wynnefield Partners Small Cap Value, L.P. I
 
2) Check the Appropriate Box If a Member of a Group (See Instructions)
(a)
(b) x Reporting Person is affiliated with other persons
 
3) SEC USE ONLY
  
4)  Citizenship or Place of Organization: Delaware
     
NUMBER OF SHARES
5) Sole Voting Power:
BENEFICIALLY OWNED
274,483 shares
BY EACH REPORTING
    
PERSON WITH
6) Shared Voting Power
   
 
    
 
7) Sole Dispositive Power:
 
274,483 shares
 
  
 
8) Shared Dispositive Power
   
 
9) Aggregate Amount Beneficially Owned by Each Reporting Person:
274,483 shares
 
10) Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
2.6%
 
12) Type of Reporting Person: PN
 

 
2
 

CUSIP NO. 218681104
   
1) Name of Reporting Person
  
 
  
Wynnefield Small Cap Value Offshore Fund, Ltd.
  
   
2) Check the Appropriate Box if a Member of a Group (See Instructions)
  
(a)
  
(b) x Reporting person is affiliated with other persons
  
   
3) SEC USE ONLY
  
 
  
4) Citizenship or Place of Organization:  Cayman Islands
  
   
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED BY
206,061 Shares
  
EACH REPORTING
  
 
PERSON WITH
6) Shared Voting Power
  
     
 
  
 
 
7) Sole Dispositive Power:
  
 
206,061 Shares
  
 
  
 
 
8) Shared Dispositive Power
  
     
 
9) Aggregate Amount Beneficially Owned by Each Reporting Person:
206,061 Shares
 
10) Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
2.0%
 
12) Type of Reporting Person (See Instructions) CO
 

 
3
 

CUSIP NO. 218681104
   
1) Name of Reporting Person
  
 
  
Wynnefield Capital, Inc. Profit Sharing Plan
  
   
2) Check the Appropriate Box if a Member of a Group (See Instructions)
  
(a)
  
(b) x Reporting person is affiliated with other persons
  
   
3) SEC USE ONLY
  
 
4) Citizenship or Place of Organization:  Delaware
 
 
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED BY
5,400 Shares
  
EACH REPORTING
  
 
PERSON WITH
6) Shared Voting Power
  
     
 
  
 
 
7) Sole Dispositive Power:
  
 
5,400 Shares
  
 
   
 
 
8) Shared Dispositive Power
  
     
 
9) Aggregate Amount Beneficially Owned by Each Reporting Person:
5,400 Shares
 
10) Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
0.1%
 
12) Type of Reporting Person (See Instructions) CO
 

 
4
 

CUSIP NO. 218681104
   
1) Name of Reporting Person
  
 
  
Wynnefield Capital Management, LLC
  
   
2) Check the Appropriate Box if a Member of a Group (See Instructions)
  
(a)
  
(b) x Reporting person is affiliated with other persons
  
   
3) SEC USE ONLY
  
 
  
4) Citizenship or Place of Organization:  New York
 
 
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED BY
489,291 Shares (1)
  
EACH REPORTING
  
 
PERSON WITH
6) Shared Voting Power
  
     
 
  
 
 
7) Sole Dispositive Power:
  
 
489,291 Shares (1)
  
 
  
 
 
8) Shared Dispositive Power
  
     
 
9) Aggregate Amount Beneficially Owned by Each Reporting Person:
489,291 Shares (1)
 
10) Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
4.7% (1)
 
12) Type of Reporting Person: OO (Limited Liability Company)
 
  
(1)  Wynnefield Capital Management, LLC holds an indirect beneficial interest in these shares, which are directly beneficially owned by Wynnefield Partners Small Cap Value, L.P. and Wynnefield Partners Small Cap Value, L.P. I.

 
5
 

CUSIP NO. 218681104
   
1) Name of Reporting Person
  
 
  
Wynnefield Capital, Inc.
  
   
2) Check the Appropriate Box if a Member of a Group (See Instructions)
  
(a)
  
(b) x Reporting person is affiliated with other persons
  
   
3) SEC USE ONLY
  
 
  
4) Citizenship or Place of Organization:  Cayman Islands
  
   
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED BY
206,061 Shares (1)
  
EACH REPORTING
  
 
PERSON WITH
6) Shared Voting Power
  
     
 
      
 
 
7) Sole Dispositive Power:
  
 
206,061 Shares (1)
  
 
  
 
 
8) Shared Dispositive Power
  
     
 
9) Aggregate Amount Beneficially Owned by Each Reporting Person:
206,061 Shares (1)
 
10) Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
2.0% (1)
 
12) Type of Reporting Person (See Instructions) CO
 
  
(1)  Wynnefield Capital, Inc. holds an indirect beneficial interest in these shares, which are directly beneficially owned by Wynnefield Small Cap Value Offshore Fund, Ltd.

 
6
 

CUSIP NO.  218681104
 
1) Name of Reporting Person
 
Nelson Obus
 
2) Check The Appropriate Box If A Member Of A Group (See Instructions)
(a)
(b)x Reporting person is affiliated with other persons
 
3) SEC Use Only
 
4) Citizenship Or Place Of Organization:  United States
 
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED
700,752 Shares (1)
  
BY EACH REPORTING
  
 
PERSON WITH
6) Shared Voting Power
  
 
0
  
 
  
 
 
7) Sole Dispositive Power:
  
 
700,752 Shares (1)
  
 
  
 
 
8) Shared Dispositive Power
  
 
0
  
   
9)  Aggregate Amount Beneficially Owned By Each Reporting Person:
  
700,752 Shares (1)
  
   
10) Check Box If The Aggregate Amount In Row (9) Excludes Certain Shares o
  
(See Instructions)
  
   
11) Percent of Class Represented by Amount in Row (9):
  
6.7%
  
   
12) Type of Reporting Person (See Instructions) IN
  
   
   
(1) Mr. Obus may be deemed to hold an indirect beneficial interest in these shares, which are directly beneficially owned by Wynnefield Partners Small Cap Value, L.P., Wynnefield Partners Small Cap Value, L.P. I, Wynnefield Small Cap Value Offshore Fund, Ltd. and Wynnefield Capital, Inc. Profit Sharing Plan because he is a co-managing member of Wynnefield Capital Management, LLC, a principal executive officer of Wynnefield Capital, Inc. (the investment manager of Wynnefield Small Cap Value Offshore Fund, Ltd.) and the portfolio manager of Wynnefield Capital, Inc. Profit Sharing Plan. The filing of this Statement and any future amendment by Mr. Obus, and the inclusion of information herein and therein with respect to Mr. Obus, shall not be considered an admission that he, for the purpose of Section 16(b) of the Exchange Act, is the beneficial owner of any shares in which he does not have a pecuniary interest. Mr. Obus disclaims any beneficial ownership of the shares of Common Stock covered by this Statement.
 
7
 
CUSIP NO.  218681104
   
1) Name of Reporting Person
  
 
  
Joshua Landes
  
   
2) Check The Appropriate Box If A Member Of A Group (See Instructions)
  
(a)
  
(b)x Reporting person is affiliated with other persons
  
   
3) SEC Use Only
  
 
  
4) Citizenship Or Place Of Organization:  United States
  
   
NUMBER OF SHARES
5) Sole Voting Power:
  
BENEFICIALLY OWNED
695,352 Shares (1)
  
BY EACH REPORTING
 
 
PERSON WITH
6) Shared Voting Power
  
 
0
  
 
 
 
 
7) Sole Dispositive Power:
  
 
695,352 Shares (1)
  
 
  
 
 
8) Shared Dispositive Power
  
 
0
  
 
9)  Aggregate Amount Beneficially Owned By Each Reporting Person:
695,352 Shares (1)
 
10) Check Box If The Aggregate Amount In Row (9) Excludes Certain Shares o
(See Instructions)
 
11) Percent of Class Represented by Amount in Row (9):
6.7%
 
12) Type of Reporting Person (See Instructions) IN
 
 
(1)           Mr. Landes may be deemed to hold an indirect beneficial interest in these shares, which are directly beneficially owned by Wynnefield Partners Small Cap Value, L.P., Wynnefield Partners Small Cap Value, L.P. I, and Wynnefield Small Cap Value Offshore Fund, because he is a co-managing member of Wynnefield Capital Management, LLC and a principal executive officer of Wynnefield Capital, Inc. The filing of this Statement and any future amendment by Mr. Landes, and the inclusion of information herein and therein with respect to Mr. Landes, shall not be considered an admission that he, for the purpose of Section 16(b) of the Exchange Act, is the beneficial owner of any shares in which he does not have a pecuniary interest.  Mr. Landes disclaims any beneficial ownership of the shares of Common Stock covered by this Statement.

8
ITEM 1(a).  Name of Issuer:

Core-Mark Holding Company, Inc.

ITEM 1(b).  Address of Issuer's Principal Executive Offices:

395 Oyster Point Boulevard, Suite 415, South San Francisco, California 94080
   
ITEM 2(a).  Names of Persons Filing:

Wynnefield Partners Small Cap Value, L.P. ("Partners")
Wynnefield Partners Small Cap Value, L.P. I ("Partners I")
Wynnefield Small Cap Value Offshore Fund, Ltd. ("Fund")
Wynnefield Capital, Inc. Profit Sharing Plan (the "Plan")
Wynnefield Capital Management, LLC ("WCM")
Wynnefield Capital, Inc. ("WCI")
Nelson Obus
Joshua Landes

ITEM 2(b).  Address of Principal Business Office Or, If None, Residence:

450 Seventh Avenue, Suite 509, New York, New York 10123
 
ITEM 2(c).  Citizenship:

Partners and  Partners I  are Delaware limited partnerships.
Fund and WCI are Cayman Islands companies.
WCM is a New York limited liability companies.
The Plan is a Delaware corporation.
Mr. Obus and Mr. Landes are United States citizens.

 
9
 


ITEM 2(d).  Title of Class of Securities:

Common Stock, $.01 Par Value Per Share
   
ITEM 2(e).  CUSIP Number:               218681104

ITEM 3.     If this Statement is filed pursuant to Rules 13d-1(b) or 13d-2(b) or (c), check whether the person filing is:

o Broker or dealer registered under Section 15 of the Act.

o Bank as defined in Section 3(a)(6) of the Act.

o Insurance company as defined in Section 3(a)(19) of the Act.

o Investment company registered under Section 8 of the Investment Company Act of 1940.

o An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

o An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

o A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);

o A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

o A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940;

o Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

This statement is filed pursuant to Rule 13d-1(c).

ITEM 4.     Ownership:

(a) Amount beneficially owned by all reporting persons:  700,752 Shares

(b) Percent of class:  6.7% of Common Stock.

(c) Number of shares as to which the reporting persons have:
(i)   sole power to vote or to direct the vote:
700,752 Shares
(ii)  shared power to vote or to direct the vote:

(iii) sole power to dispose or to direct the disposition:
700,752 Shares

 
10
 

(iv)  shared power to dispose or to direct the disposition:

ITEM 5.  Ownership of five percent or less of a class.

Not applicable.
 
ITEM 6.  Ownership of more than five percent on behalf of another person.

Not applicable.
 
ITEM 7.  Identification and classification of the subsidiary which acquired the security being reported on by the parent holding company.

Not applicable.
 
ITEM 8.  Identification and classification of members of the group.

See Item 2 (a) - (c).
 
ITEM 9.  Notice of dissolution of group.

Not applicable.

 
11
 

ITEM 10.  Certifications.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection or as a participant in any transaction having that purpose or effect.

 
12
 

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.
 
Dated:   February 12, 2010
 
 
     
By:  
Wynnefield Capital Management, LLC, General Partner
  
       
 
By:  
/s/ Nelson Obus
  
   
Nelson Obus, Managing Member
  
       
WYNNEFIELD PARTNERS SMALL CAP VALUE, L.P. I
  
       
By:
Wynnefield Capital Management, LLC, General Partner
  
       
 
By:
/s/ Nelson Obus
  
   
Nelson Obus, Managing Member
  
       
WYNNEFIELD SMALL CAP VALUE OFFSHORE FUND, LTD.
       
By:
Wynnefield Capital, Inc.
  
       
 
By:
/s/ Nelson Obus
  
   
Nelson Obus, President
  
       
WYNNEFIELD CAPITAL, INC. PROFIT SHARING PLAN
  
       
 
By:
/s/ Nelson Obus
  
   
Nelson Obus, Portfolio Manager
  
       
WYNNEFIELD CAPITAL MANAGEMENT, LLC
  
       
 
By:
/s/ Nelson Obus
  
   
Nelson Obus, Co-Managing Member
  
       
WYNNEFIELD CAPITAL, INC.
  
       
 
By:
/s/ Nelson Obus
  
   
Nelson Obus, President
  
       
/s/ Nelson Obus
  
Nelson Obus, Individually
  
   
 
Joshua Landes, Individually
  

 
13