Job-Market signaling is ranked high among the explanations why in- dividuals engage voluntarily in OSS projects. If true, signaling implies the existence of a wage premium for OSS engagement. However, due to a lack of data this issue has not been tested previously. Based on a novel data set comprising detailed demographic and wage information for some 7,000 German IT employees, this paper fills this gap. In the empirical analysis, however, we find no support for the signaling hypoth- esis, a result that is robust to different measures of OSS involvement and different model specifications.