Retail rents are tumbling in Manhattan, especially in the toniest neighborhoods. In the area around the Plaza Hotel on Fifth Avenue, home to the borough’s priciest retail real estate, rents fell 13.5 percent in the second quarter from the previous three months, the largest decline among the 16 neighborhoods tracked by brokerage CBRE Group Inc. The drop was due in part to a single space that had its price cut from $3,500 a square foot to $2,500, CBRE said in a report Tuesday. Tenants have the upper hand in New York as landlords contend with a record number of empty storefronts. Across Manhattan, 143 retail slots have sat vacant for the past year, and rents have been reduced on more than half of those spaces, CBRE said. Property owners are increasingly willing to negotiate flexible terms in an effort to get tenants to commit to leases, according to the report. Read more at Bloomberg.