Fidelity Investments, the nation’s largest privately held...

Fidelity Investments, the nation’s largest privately held investment management and discount brokerage firm, said it has signed an agreement to purchase Provident Mutual Variable Life Insurance Co. from Provident Mutual Life Insurance Co. of Philadelphia. The purchase price was undisclosed. . . . AT&T; introduced a new microprocessor, the WE 32200, that it said is faster than any 32-bit chip now available . . . The Federal Reserve reported that the average yield for one-year Treasury bills, the most popular index for making changes in adjustable rate home mortgages, dipped to 5.77% last week after averaging 5.79% the week before.