Cevian Capital, Europe’s most prominent activist investor, has cut its stake in UK-based Vodafone (NASDAQ:VOD) as scepticism grows that the telecoms company will be able to reverse its sluggish performance.

Last year, Cevian made a significant but undisclosed stake in Vodafone through shares and derivatives. With this, it became one of the ten largest shareholders.

As per media reports, Cevian Capital pushed Vodafone’s management to simplify its international portfolio and sell poorly performing divisions. However, the investor sold the vast majority of its stake by June. Both Vodafone and Cevian Capital did not immediately respond to requests for comment.

Earlier in January, the media reported that Abrdn, Vodafone’s other most significant shareholder, supported Cevian’s call for restructuring.

A Swedish investment company founded in 1996 by Christer Gardell and Lars Förberg, Cevian Capital is backed by Carl Icahn. It is the largest activist investment firm in Europe, with offices in Stockholm, Zurich, and London.