Madison Dearborn Partners has already worked with Soros Private Equity on a number of deals and, according to Irish financial newspapers, is keen to join forces again. Madison declined to comment.

Soros is president and chairman of Soros Fund Management LLC, a private investment management firm that is principal adviser to the Quantum Group of Funds, a series of international investment vehicles.

Chicago-based Madison appears keen for Jefferson Smurfit Group chairman Michael Smurfit to remain involved in the company, along with other members of the Smurfit family.

Shares in the Irish packaging firm were down 1.8% on the news to 196.5p.

Madison Dearborn is one of the largest financial investors in paper and packaging, with interests in five firms.

Story by Andy Scott