(b), (c), (d) and (e) On September 14, 2012, Mr. J. Michael Walsh informed Core-Mark Holding Company, Inc. (the "Company") that he would be retiring as President and Chief Executive Officer of the Company, to be effective as of January 18, 2013. Mr. Walsh has served the Company as President and Chief Executive Officer since March 2003 and as a member of the Board of Directors (the "Board") since August 2004. Mr. Walsh will continue to serve as a director on the Board after his retirement as an officer. The Company has named Mr. Thomas B. Perkins as President and Chief Executive Officer to succeed Mr. Walsh. In connection with his promotion, Mr. Perkins also will be appointed to the Board. Mr. Perkins, who has been with the Company since August 1993, has served as the Company's Vice President - Resources since June 2007. Effective January 18, 2013, Mr. Perkins' annual base salary will be increased to $450,000, with an annual performance bonus opportunity of 125% of annual base salary. In addition, effective January 18, 2013, Mr. Perkins will receive a one-time grant of 10,000 restricted stock units to be issued under the Company's 2010 Long-Term Incentive Plan, a one-time relocation bonus of $100,000, and reimbursement of out-of-pocket expenses incurred in connection with his relocation from Phoenix, Arizona to the Company's corporate headquarters in South San Francisco, California. One-third of Mr. Perkins' newly-issued restricted stock units will vest on the first anniversary of the date of grant, with the remaining two-thirds vesting in equal quarterly installments based upon a regular calendar period over the following two years (2014 and 2015).

(d) Exhibits.

Number     Description
99.1       Press Release of Core-Mark Holding Company, Inc.,
           dated September 18, 2012