All the attention over the past month has been on property tycoon Robert Tchenguiz, who has built his stake to about 5 per cent, but the key player now is Qatari investment fund Delta Two, which now owns a quarter of the supermarket.
This is a serious holding and a big headache for Sainsbury's management and the Sainsbury family, because there is little doubt that the plans of Delta (and for that matter Tchenguiz) are at odds with their strategy.
In simple terms, the new investors are interested in property. They know the value of the Sainsbury's property portfolio and want to exploit it. The management and the family think that freehold ownership is intrinsic to the success of the business and crucial if Sainsbury's is to prosper in its battle with Tesco and Asda.
This argument enabled the family to rebut the private equity raiders back in April, but they didn't have a combined stake of more than 30 per cent. And while Tchenguiz is not acting in concert with Delta, it is worth noting that his brother Vincent has been retained as the adviser to the government of Qatar on its property investments in the UK over the past few years.
No one knows what Delta will do next, but the present situation cannot be sustained for long, when such a big shareholder's views are so fundamentally at odds with the family and the management. But now that the Sainsbury family has been overtaken as the company's biggest shareholder by Delta, it finds itself in a rare position of vulnerability.
DSGi chief executive John Clare is known as one of the hard men of retail, but delegates at the British Retail Consortium's conference on the secrets of retailing success yesterday will have seen a different side to the man.
Clare, who is stepping down in September, showed signs of emotion as he talked about his 22 years at the electronics retailer. It has been a hard slog and not everything has worked, but his stewardship has transformed a business that could have been destroyed by the internet revolution.