Aby Rosen’s RFR and Kushner Companies sold a stake in 81 Prospect Street, part of their Dumbo office portfolio, to Pearl Realty’s Jack Guttman for $33.8 million. This sale follows a $480 million refinancing package for the four-property portfolio, which includes 55 Prospect Street, 117 Adams Street, and 77 Sands Street. The refinancing came after the landlords defaulted on a $180 million CMBS loan and faced difficulty repaying additional loans. The Dumbo portfolio’s value dropped to $207 million from $640 million five years ago, with occupancy falling to 73%. Key tenants include Etsy and Brooklyn Laboratory Charter Schools