Blackstone, KKR and CVC have said they are 'in the preliminary stage of assessing Sainsbury's'.
Sainbury's shares jumped 18 per cent to 526p after the announcement earlier this morning. The shares have since fallen back to 514.25p.
Speculation that Sainsbury's could be a bid target emerged earlier this week when Numis issued a note that said it was 'highly likely' that property and financial investors were running a slide rule over the business and that they could afford to offer as much as 600p if the property was sold and leased back.
Yesterday, Lord Sainsbury of Turville sold a 3 per cent stake in the chain, raising£176 million and intensifying speculation that a potential bidder could have snapped up the stock.
Sainsbury's said that the sale of the holding was 'a result of the settlement of contractual arrangements entered into with a leading investment bank'.
The sale means that Lord Sainsbury is no longer the largest shareholder in the group. Axa Investment Management is the biggest stakeholder, with 15.4 per cent.