JetBlue shares rise before market open as activist investor Carl Icahn takes a stake in the airline

Shares of JetBlue are rising more than 15% before the market open on Tuesday as activist investor Carl Icahn took an almost 10% stake in the airline.

Icahn, who purchased the shares in January and February, said in a regulatory filing that he believe JetBlue's stock is undervalued and represents an attractive investment opportunity. The stock is down abut 29% in the past year.

He has had talks, and plans to continue talking with JetBlue in regards to possible representation on its board of directors.

JetBlue did not immediately respond to an email seeking comment.