We use the data leak of the Panama Papers on April 3, 2016 to study whether and how the use of secret offshore vehicles affects firm value around the world. The data provide insights into the operations of more than 214,000 shell companies incorporated in tax havens by Panama-based law firm Mossack Fonseca. Using event study techniques, we find that the data leak erases US$135 billion in market capitalization among 397 public firms with direct exposure to the revelations of the Panama Papers, reflecting 0.7 percent of their market value. Tax aggressive firms and firms with exposure to perceptively corrupt countries are more adversely affected. This is consistent with the leak (i) reducing firms’ ability to avoid taxes and finance corruption, or (ii) increasing regulatory fines for past tax evasion and violations of anti-corruption regulations. Taken together, secret offshore vehicles are used for value-enhancing but potentially illegal activities that go beyond tax avoidance. Offshore intermediaries facilitate such activities.
