Private equity firm Bridgepoint Capital, the largest shareholder of Safestore, said it planned to sell up to 32m shares, or about half its stake in the British self-storage retailer.
The shares represent about a 17 per cent stake in Safestore, Bridgepoint said, adding that it would continue to hold at least 17.9 per cent shares in Safestore after the deal.
The investor said it would not sell further Safestore shares for 90 days.
Bridgepoint said the bookrunner for the placing is JP Morgan Cazenove and that the placing price would be disclosed shortly.
Safestore, which was listed initially in 1998, was taken private via a management led buyout for £39.8m by chief executive Steve Williams and Bridgepoint in August 2003.