The Federal Circuit once capped the penalty for violating the marking at $500 for each action of false marking (no matter how many articles were marked). However, the good old days are now gone.
As enunciated by the Federal Circuit in The Forest Group, Inc. v. Bon Tool Co., __ F.3d __ (Fed. Cir. 2009)(Moore, J.) on December 28, 2009, the court interpreted the 1952 amendment of the marking statute to hold that each violation of the marking statute under 35 U.S.C. § 292(a) occurs for each article sold: “Whoever marks … any unpatented article [with] the word ‘patent’… for the purpose of deceiving the public . . . shall be fined not more than $500 for every such offense.”
Now, $500/article…that can be a lot of money!