By | May 18 2012 7:06 AM

A widely held swath of tax-exempt Puerto Rican bonds may be downgraded within weeks, a Wells Fargo credit strategist said. If it occurs, the move could cripple the portfolio strategies of small and large global investors who have purchased the popular instruments as a way to chase high-yield securities and diversify geographically without dipping into the lower end of the investment grade pool.