Moody’s Investors Service Inc. said it lowered...

Moody’s Investors Service Inc. said it lowered the long-term debt ratings of Delta Air Lines Inc., assigned a Baa3 rating to a proposed issue of convertible preferred stock and confirmed the company’s Prime-2 rating for commercial paper. . . . Sales of U.S. savings bonds in May were $916 million, a 9% rise over May, 1991, the Treasury said. Sales since January have totaled $5.67 billion. . . . Moody’s Investors Service Inc. said it placed the long-term debt ratings of AMR Corp. and its wholly owned subsidiary, American Airlines Inc., under review for possible downgrade. . . . Pfizer Inc., New York, has completed the previously announced sale of its Coty fragrance and cosmetics business to Joh. A. Benckiser GmbH for $440 million in cash.