In this paper, I investigate whether participation in employee stock option exchange programs contains private information about future stock returns. High participation in employee stock option exchange programs is associated with negative future abnormal returns over the ensuing 12-month period. This association is moderated by the transparency of the firm's information environment: high institutional ownership and high financial statement informativeness weaken the negative relation between participation and abnormal returns. Controlling for transparency of the firms' information environment, the association between participation and future returns arises primarily from firms that allow the CEO to participate.