Prudential created a new business unit that will manage $145 billion in fixed-income assets worldwide for institutional, retail and insurance accounts, of which $55 billion is U.S. institutional tax-exempt, according to Prudential spokesman Tim Biggs. Prudential Global Asset Management, Fixed Income, will be co-managed by James Sullivan and Jack Gaston. Mr. Sullivan will be responsible for all portfolio management and credit research; he formerly was in charge of all fixed-income portfolios for external clients. Mr. Gaston will be responsible for the new groups risk management and quantitative research; he previously was head of Prudentials Capital Management Group. Capital Management, which handles the investment of general insurance assets in fixed-income issues, will be merged with the fixed-income group that manages institutional and retail assets to create the new unit. Prudential managed nearly $120 billion in institutional tax-exempt assets as of year-end 1998, with $40 billion in active domestic fixed-income investments; $1.5 billion in active foreign bonds; and $1.5 billion in high-yield bonds.