Activist hedge funds, which once instilled fear in corporate boardrooms across the globe, are baring their teeth again after a few quiet years. But the aggressive stances of yesteryear are in many cases being replaced with a more softly-softly approach.

In November, Chris Hohn's activist hedge fund The Children's Investment Fund ousted the chairman of Australia's Infigen Energy, marking the return to activism for the firm after being quiet for over a year. Last Wednesday, Barington Capital, an activist hedge fund, called for the ousting of Ameron International chief executive James Marlen.