The UK’s Competition Commission has sent out letters to the potential bidders for UK supermarket chain Safeway explaining the issues it is considering in its investigation.

The competition regulator said it has received further evidence from the interested parties, their competitors and other interested organisations and individuals but has not yet reached any conclusion on the matter. It is still considering whether to block any of the bids or enforce store disposals.

UK supermarket operators Tesco, Sainsbury’s, William Morrison and Wal-Mart’s Asda have all expressed interested in bidding for Safeway. The Commission is investigating the possible effect on the UK’s supermarket sector of each of the potential outcomes.

The regulator hinted it may prefer Wm Morrison to the other supermarket chains as a suitor for Safeway. “A Morrison/Safeway merger could be pro-competitive in creating a powerful fourth national player,” the Commission was quoted by Reuters as saying.

The investigation is due to end on 12 August, but this deadline may be extended.