We study the impact of mandatory disclosure of contributions paid by interested third parties to decision makers such as doctors, politicians, or financial advisors. While transparency is commonly viewed as a means of reducing potential conflicts of interest, our analysis reveals less benign outcomes when multiple third parties attempt to influence decision makers in opposing directions. We argue specifically that in this case transparency enables competing third parties to establish separate spheres of influence, where their ascendancy is not attenuated by the opposing efforts by rivals. Consequently, decision makers' choices become more polarized. We apply this theory to the market for anticoagulants, using data on prescriptions and payments made by pharmaceutical companies to doctors in the United States before and after the Physician Sunshine Act of 2010 that mandated payment disclosure. The empirical analysis supports our theory. We study the impact of mandatory disclosure of contributions paid by interested third parties to decision makers such as doctors, politicians, or financial advisors. While transparency is commonly viewed as a means of reducing potential conflicts of interest, our analysis reveals less benign outcomes when multiple third parties attempt to influence decision makers in
opposing directions. We argue specifically that in this case transparency enables competing third parties to establish separate spheres of influence, where their ascendancy is not attenuated by the opposing efforts by rivals. Consequently, decision makers' choices become more polarized. We apply this theory to the market for anticoagulants, using data on prescriptions and payments made by pharmaceutical companies to doctors in the United States before and after the Physician Sunshine Act of 2010 that mandated payment disclosure. The empirical analysis supports our theory.