The coin has been making its second appearance at market, the initial ran July 30, 2002, at Sotheby's New York auction gallery, in conjunction with Stack's.
This is a breaking news story. Coin World is going to have more details about the auction after.
Editor's Note: This story was updated to reflect a new price for the coin. The original price of $19,509,750 released by Sotheby's was then lowered to $18,872,250.