The two largest shareholders in J Sainsbury have taken this week's spike in the retailer's share price as an opportunity to trim holdings and lock in profits, as hedge fund investors raised their stakes following yesterday's "put up or shut up" demand by the UK's takeover regulator.

J Sainsbury, which is being pursued by a private equity consortium led by Blackstone and including CVC Capital Partners and Kohlberg Kravis Roberts, saw its shares rise to a nine-year high of 539p yesterday on rumour that another investor may be considering a bid.