No Registration Prior to Infringement.
Under 17 USC 504(b) as modified by 17 USC 412, if the copyrightable work was not registered with the U.S. Copyright office when the infringement occurred, then the copyright holder is only entitled to actual damage and profits made from the infringement. To establish the infringer's profits, the copyright owner is required to prove the infringer's gross revenue, which can be difficult depending on the type of copyrightable work.
Valid Registration Prior to Infringement.
If the work was registered with the copyright office before the infringement occurred, then the copyright holder is entitled to claim either (at the copyright owner's choice): (A) actual damages and profits, or (B) statutory damages - The court may at its discretion set a penalty of $750 to $30,000+ per infringement. Upon a showing of willful infringement, the court may increase the penalty to $150,000 per infringement. (Plus attorney fees)