Exco Resources Inc. (NYSE:XCO), rejected a $4 billion offer from Chief Executive Officer Douglas H. Miller and is ending its process to search for a buyer after getting no offers that were in the shareholders' interest.Miller completed a cash offer of over $4.4 billion, or $20.50 a share for Exco last October but he condensed his bid around 10% to $18.50 a share.A special board committee definitively agreed the modified bid was too low and rejected Miller’s bid on Friday, and voted to keep Exco a public company.Miller said, "I don't necessarily disagree with them but that was the highest offer we could put in. Early on I felt oversubscribed and as it went on I think we started losing some people and at the end we lost a major player, which resulted in us bidding $18.50."EXCO Resources has a potential upside of 40.1% based on a current price of $16.2 and an average consensus analyst price target of $22.7.