This closely watched investor is a fan of retail-based enterprises.Due to laws and regulations overseen by the Securities and Exchange Commission (SEC), large asset managers are required to publicly disclose their equity positions within 45 days of a quarter's end. For the retail investor, this is a potential gold mine of possible stock ideas.One well-known hedge fund manager, Bill Ackman, who heads Pershing Square Capital Management, is closely watched. His track record has made him somewhat of an investin ...