DUESSELDORF (Reuters) - Activist investor Cevian took part in Thyssenkrupp's (>> ThyssenKrupp) 1.38 billion euro (1.21 billion pounds) share sale, a person familiar with the matter told Reuters on Tuesday.

With a stake of about 18 percent, Cevian is Thyssenkrupp's second-largest shareholder behind the Alfried Krupp von Bohlen und Halbach Foundation, which holds about 23 percent.

The foundation declined to comment when asked whether it took part. If not, it would dilute its stake to about 21 percent. The foundation did not participate in Thyssenkrupp's last share sale in 2013.

Thyssenkrupp said late on Monday it was increasing its capital by 10 percent to help fund the industrial goods businesses that will stay with the firm after the planned merger of its steel operations with Tata Steel (>> Tata Steel Limited).

(Reporting by Tom Kaeckenhoff; Writing by Christoph Steitz; Editing by Georgina Prodhan)

Stocks treated in this article : ThyssenKrupp, Tata Steel Limited