John McFadden and Robert Miller, SVPs in the local office of CB Richard Ellis, represented the seller. "The price sets a new benchmark for Philadelphia residential," McFadden tells GlobeSt.com, adding, "the cap rate is below 5%, which is also an historical benchmark."

The local office of Marcus & Millichap projects a $58,000 median price-per-unit for multifamily sales throughout the Philadelphia MSA this year. That median rose 24% last year and 19% the year before. The only recent sale that even approaches Domb's ticket for 2031 Locust is a small, nine-unit property in West Chester, PA, which, according to M&M data, traded for $150,000 a unit.

The Locust St. building is part of the 15-property multifamily portfolio Morgan acquired from locally based Pennsylvania Real Estate Investment Trust. At the time, PREIT exited the multifamily market to become a retail-only REIT. GMACCM arranged $313 million in debt financing for Morgan's purchase of the portfolio, and, on the advice of its subsidiary, GMAC Institutional Advisors LLC, also made a $90-million equity investment in the portfolio. Proceeds from this sale will be used to pay down the GMACCM debt.