Carrie Driebusch

Trian Fund Management LP, a hedge fund known for pushing big companies to make operational and other changes, has launched an activist campaign against Comcast in a bet that the cable-TV and entertainment giant’s stock is undervalued. Trian has accumulated about 20 million shares in Comcast, for a roughly $900 million stake or about 0.4% of the company. Comcast’s market value is about $200 billion. Executives at Trian -- which was founded by Nelson Peltz, Ed Garden, and Peter May -- recently began conversations with Comcast management.