...+ Standard & Poor's Ratings Services believes a step-up in efforts by an activist investor to split businesses at DuPont (E.I.) De Nemours & Co. increases the risk of a potential deterioration in credit quality. + We are affirming our ratings on DuPont, including the 'A' long-term corporate credit rating. + We are revising the outlook on the corporate credit rating to negative from stable. NEW YORK (Standard & Poor's) Jan. 12, 2015--Standard & Poor's Ratings Services said today it revised its outlook on DuPont (E.I.) De Nemours & Co. to negative from stable. At the same time, we affirmed our 'A' long-term corporate credit rating and other ratings on the company. The outlook revision reflects our view that credit risk at our 'A' corporate credit rating on DuPont has increased, following a step-up in an activist investor's effort to gain influence at the company. That investor, Trian Fund Management, announced recently its intention to nominate four individuals for election to DuPont's Board...