NEW YORK, Dec. 4 -- Optical Cable Corp. said Robert Kopstein has been removed as chairman, president and chief executive after its board of directors learned he had pledged some of his Optical shares to secure personal loans. The company formed a special committee in early October after learning Kopstein had pledged "substantially all of his personally held unregistered shares of the company to secure substantial personal margin loans from several brokerage firms," Optical said in a release. "Because of the time and attention necessitated by the ongoing disputes with the brokerage firms and the ensuing litigation, it became apparent to the special committee that Mr. Kopstein could not devote his focus and attention to his duties." Kopstein has been asked to remain as an outside consultant based on the "significant role" he has in the company. Neil Wilkin, current senior vice president and chief financial officer, be acting president until a successor to Kopstein is named.