Last week, the UK's biggest supermarket made a£155.6 million offer for Dobbies, at a price of 1,500p a share in cash, which was recommended by Dobbies' shareholders.
Hunter is believed to have raised his stake in Dobbies from 10.6 per cent to 20.6 per cent by buying shares at 1750p.
Seymour Pierce analyst Richard Ratner outlined three possible scenarios. Ratner said: 'Hunter could counter bid, but given Tesco's firepower and the fact that in the past he has said that 1500p a share was too much, we wonder whether this is a likely course of action. Secondly, he could be doing it to force Tesco to raise its offer - remember that his original stake cost less than 1200p a share - and he would therefore make a decent profit. We suspect that Tesco will raise its offer to try to stop him buying more shares.
'Finally, he may be doing this in order to frustrate Tesco from getting Dobbies at any price. There is only one serious retailer in this sector: Hunter. He may well be fearful of having Tesco as a competitor. Thus, were he to get to 25 per cent, it could scupper the deal entirely.'