$63.3 billion Target Corporation is bracing for a “costly and disruptive” proxy battle for control of five spots on the retailer’s board of directors. Initiating the fight is activist investor William Ackman of Pershing Square Capital Management, Target’s third-largest investor.

The five-member slate announced March 17 includes Ackman; Jim Donald, former CEO of Pathmark and Starbucks; Michael Ashner, CEO of Winthrop Realty Trust; Ronald Golson, a Stanford Law School professor; and Richard Vague, the former CEO of First USA bank. If elected, Ackman’s nominees will hold five of the 13 seats on Target’s board.

Ackman has long argued that Target’s stock is undervalued. “We believe that our nominees will bring insight, accountability, and fresh and relevant perspectives to the Target board,” Ackman said in a statement. “If elected, we believe they will substantially improve Target’s ability to navigate through the current economic environment while increasing shareholder value over the long term.”

Target, however, has refused to recommend Ackman, or his nominees, for its board. Instead, the company recommended the re-election of four directors whose terms expire on May 28. Those directors are McDonald’s executive Mary Dillon; Wells Fargo Chairman Richard Kovacevich; Telstra CEO Solomon Trujillo; and George Tamke, a partner at private equity firm Clayton Dubilier & Rice.