 NEW YORK--BUSINESS WIRE--Halper Sadeh LLP, a global investor rights law firm, is investigating whether the sale of Core-Mark Holding Company, Inc. NASDAQ: CORE to Performance Food Group Company is fair to Core-Mark shareholders. Under the terms of the merger, Core-Mark shareholders will receive 23.875 per share in cash and 0.44 Performance Food shares for each Core-Mark share. Upon closing, Core-Mark shareholders will own approximately 13 of the combined company. Halper Sadeh encourages C 