Morrisons' share price has surged by 28% after a US private equity firm made an offer to buy the supermarket group for £5.5bn.
The shares closed at 228p on Monday, just below the 230p-a-share proposed by Clayton Dubilier & Rice.
Morrisons' board has rejected the offer, saying it "significantly undervalued" the business "and its future prospects".
However, there is speculation the move may prompt others to bid for the group.
Morrisons - the UK's fourth-largest supermarket chain - has nearly 500 shops and employs about 118,000 people.
Morrisons has had a relationship with Amazon since 2016, under which the supermarket sells fresh produce and food through Amazon's website.
Executive editor of the publication Retail Week, said: "Amazon hasn't, so far, really become a force to be reckoned with in food but it would like to be. You wonder whether this situation might flush out interest from them."
Amazon owns the US supermarket chain Whole Foods, which also has seven outlets in the London.
