SHARES in supermarket group Sainsbury closed 34.5p higher at 515.5p after it announced the sale of its 20% stake in American supermarket chain Giant. This comes just days after Sainsbury said it was ''well placed'' with Giant to expand its US interests.

The surprise #375m deal means Sainsbury will make a #100m profit after only three-and-a-half years of involvement with Giant.

Sainsbury, which made no mention of a possible deal when it announced its 1997 results two weeks ago, said it was ''in our shareholders' best interests''.

The buyer is Dutch supermarket giant Ahold, which one of Europe's leading players in the international food retailing business.

Sainsbury chief executive Dino Adriano said: ''Taking control of Giant was a desirable but not essential element of our US growth strategy.'' He said the company would now concentrate on Shaws, its other American business which, like Giant, is based in New England.