Activist hedge funds, especially those which engage in hostile campaigns, are leaving the companies in which they are pushing for change with reduced rather than improved performance, according to a new research paper.

The topic of whether activist hedge funds deliver long​-term value for investors in the companies they target is a controversial and hotly debated one: supporters argue that hedge fund activists pursue a small number of companies and often have a large amount of their personal money invested, and that they have a special skill at identifying and turning around poorly performing companies. Critics, in contrast, argue that such funds are impatient and motivated by short-term goals.