Penn National Gaming stock has been down about $1 per share Tuesday on speculation it may be a potential buyer of a $400 million casino company.Hollywood Casino, a publicly held company with properties in Illinois, Mississippi, and Louisiana, reportedly hired an investment bank two weeks ago to find potential buyers, according to Reuters news service. A company spokesman declined to comment.As of 3 p.m. Tuesday, Penn National's stock (Nasdaq:PENN) was down $1.02 to $34.20, a drop of about 3%.Other suitors for the Dallas-based company include Harrah's Entertainment, a co-owner of Turfway Park in Northern Kentucky, and Ameristar Casinos. MGM Mirage and Park Place also have expressed interest, particularly in Hollywood Casino's Chicago area casino.Hollywood Casino (AMEX:HWD) has a current market capitalization of about $400 million, plus another $435 million in debt, which would value a deal, including assumed debt, at about $835 million at its current trading price of about $16. Any premium the company is likely to seek would likely push the deal value, again including debt, closer to $1 billion, analysts said.Since mid-December, Hollywood Casinos shares have nearly doubled from the $9 range to their current level, partly on speculation about a potential sale as well as optimism about a replacement casino now being built on the Aurora site near Chicago.Rumors of a sale have surfaced periodically in recent months, most recently in February when Hollywood said it had filed two lawsuits connected with activities of two of its directors and former officers.In the suits, the company accused former chairman and chief executive officer Jack Pratt, William Pratt, Harold Simmons and their affiliates of violating federal securities laws.The suits allege the defendants were planning a proxy contest at the company's annual meeting without properly reporting such activities. Affiliates of Simmons also are accused of acquiring between 4% and 5% of Hollywood Casino stock while in possession of non-public information about the company. The Pratts collectively own about 34% of the company's common shares.A Hollywood Casino press release about the suit did not offer any more details. The suits also alleged that affiliates of Simmons acquired between 4 percent and 5 percent of the company's stock "while being in possession of material non-public information regarding the company." It said the two Pratts collectively own about 34 percent of the company's common shares.