Enron's recent woes had many investors factoring in a credit-rating reduction. ''This move was anticipated,'' said Mike Dineen, who holds Enron bonds in the $5 billion of fixed-income assets he helps manage at the Mony Life Insurance Company. Enron's long-term credit ratings outlook was changed last week to negative from stable by Standard & Poor's. S.& P. affirmed the company's rating of BBB+, the equivalent of Moody's Baa1.