...+ DuPont (E.I.) De Nemours & Co. has announced its intention to increase its stock buybacks through 2016 by at least $4 billion. The company will fund the additional buybacks, which are not part of an existing repurchase program, with proceeds from the announced sale of its specialty chemical unit. + We assume the buybacks will be somewhat evenly spread out across 2015 and 2016 + We are affirming our ratings on DuPont, including the 'A' long-term rating based on our expectation that the company will maintain key leverage credit measures such as funds from operations (FFO) to total net debt above of 35%, while implementing its recently announced share-buyback plan. + The negative outlook reflects the risk that leverage measures may weaken beyond our expectations, and our view that risks to credit quality may increase due to stepped-up efforts by an activist investor. NEW YORK (Standard & Poor's) Jan. 27, 2015--Standard & Poor's Ratings Services said today it affirmed its ratings, including...