Sir Ken Morrison, the former chairman of Morrisons, has bought a hefty stake in rival Sainsbury's.
The news came to light on the day that Bradford-based Morrisons gets relegated from the London Stock Exchange’s elite FTSE 100 index following falling sales, profits and market share.
Sir Ken and his son William have acquired 4.7 million shares in Sainsbury's, giving them a £12m stake in the firm.
Sainsbury's is the only one of the big four supermarkets to be gaining market share while rivals Tesco, Asda and Morrisons lose shoppers to discounters Aldi and Lidl.
Sir Ken holds 2.6 million shares worth £6m and has given Mike Coupe, the chief executive at Sainsbury's, his public backing. Sir Ken's son William holds the remainder.
Sir Ken purchased his stake around April last year, before the appointment of David Potts as Morrisons' new chief executive.
Speaking about the Sainsbury's share purchase, Sir Ken told The Times: "It is a well-run company."
Morrisons, the UK’s fourth biggest grocer, will be replaced in the FTSE 100 today by credit lender Provident Financial, which is also based in Bradford.
The grocer narrowly missed relegation in the June and September reviews and the demotion ends 14 years in the top flight.
Sir Ken has given his public backing to Mr Potts, who joined Morrisons in March. Mr Potts has taken the axe to managerial roles and hired an extra 5,000 shop staff.