Listed company chief executives know that fighting activist hedge funds can be expensive and campaigns fought out through the media can irreparably damage a company’s reputation. But being an activist investor also has its risks.

These firms tend to put all their efforts into just a few investments a year and often have to resort to threats of going to the media with damaging comments in order to force company management to agree to changes, even though this could hurt the share price of the company they are invested in rather than improving it.