Recent studies have looked at the private donating behavior of lobbyists to better understand the level of partisanship in the interest group environment, finding that individual lobbyists and the firms they work for are increasingly polarized along party lines. In this study, I examine whether the identity characteristics of the interest groups for whom they lobby affects the private behavior of lobbyists. In particular, I adopt Heaney's (2004) typology of interest group branding strategies, and find that the interest groups for whom lobbyists work impacts their private donating behavior.