Lost Margin appears as a visible dark border around certain player records within the Bureau's system. Other players can see its dimensions but never access its contents - creating asymmetric intelligence where everyone knows secrets exist but no one knows what they are. The margin grows larger when more information was suppressed, with larger margins indicating more significant hidden data. The void has a distinctive halftone dot border pattern that marks it as Bureau-certified suppressed content.

Lost Margin serves as a permanent indicator that information was suppressed from a player's record - it enables the core 'Trust No One' mechanic by allowing competitors to see that secrets exist without being able to verify what those secrets contain. Players with large margins become targets for those seeking to uncover Bureau secrets, while those with small margins remain mysterious.