STOCKHOLM (Reuters) - The head of activist fund Cevian Capital said on Monday that shares in Swiss engineering group ABB could be worth more than 35 Swiss francs (£29.88) if newly appointed CEO Bjorn Rosengren succeeds in raising margins and valuations to that of rivals.

The shares closed at 17.53 francs on Friday.

"ABB's problem is that margins and valuation multiples are considerably lower than rivals in each business area," Cevian managing partner Christer Gardell said in an emailed statement.

"If these gaps are closed, ABB should be worth more than 35 CHF. That is Bjorn's main task."

Cevian is ABB's second largest shareholder with a 5.3% stake.

(Reporting by Simon Johnson; editing by Jason Neely)