New York City Retirement Systems issued an RFP for at least one debt-based manager to handle economically targeted investments. The size of the allocations has not been determined. The investments would target low- to middle-income housing and community development in the city, according to Laura Rivera, spokeswoman for the $74 billion system. The RFP was issued by the office of William C. Thompson, city comptroller and custodian and investment adviser to the systems, and is available at www.comptroller.nyc.gov/bureaus/bam/rfps.shtm. No due date has been set.