Activist investor Primestone urges Tennant to merge with Nilfisk

"Primestone Capital owns more than 5 percent of both Tennant and Nilfisk and believes a combination of the two will generate extraordinary returns for shareholders," the London-based activist firm said in a filing with the U.S. Securities and Exchange Commission. It disclosed it had taken a 5.2 percent stake in Tenant.

Tennant confirmed Primestone's stake in the company and said its board would carefully evaluate the activist firm's views.

Nilfisk, which was spun off from Danish cable maker NKT in October, was not immediately available to comment.

Nilfisk's shares closed up 7 percent in Copenhagen, while Tennant shares were up 1.3 percent in afternoon trading.

Primestone said it believed a merger would create earnings per share (EPS) accretion in excess of 85 percent for both companies.

It is following a trend, as 91 European companies have been subject to activist campaigns this year as of the end of November, according to industry tracker Activist Insight.

Primestone Capital, which does not disclose its assets under management, was set up in December 2014 by former Carlyle Group senior partners Franck Falézan, Benoît Colas and Jean-Pierre Millet.

Primestone owns a 5.6 percent stake in Nilfisk.

(Reporting by Stine Jacobsen in Copenhagen and Maiya Keidan in London, editing by Louise Heavens and Susan Fenton)