Shares in Downer EDI have soared following an upgrade to the engineering group's full-year profit guidance after it found larger-than-expected cost savings following its Spotless purchase.

Downer, which owns an 87.8 per cent stake of Spotless since finalising its takeover in August, upgraded its net profit guidance to $195 million, from April’s $190 million, after a review identified $25 million of cost savings and “significant” revenue opportunities. But the company expects Spotless’s profit to be at…