It should also be noted that manufacturers sometimes issue additional series to regular sets that may also include rookie cards. Rookies released in this fashion are designated as being XRC's (extended rookie cards). For star players, the XRC cards in no way diminishes demand and as a result often see increases in value much like the rookie cards in a regular set. As the current sole licensee of baseball cards, Topps has introduced new terminology in an attempt to differentiate a player's rookie prospect card from their official MLB issue ones by terming the former "First Year" cards. This is to distinguish between a player's first-year for having cards produced in an MLB set from a player's actual MLB rookie year which can often be several years after the first card is produced.