10,218 Multifamily Units Under Construction Amidst Rising Boston Vacancy Rates

Greater Boston's multifamily market faces a softening trend, with vacancy rates climbing to 6.9 percent in the first quarter of 2026. According to a Colliers report, rental growth has slowed to 0.3 percent year-over-year, while lease concessions have climbed to 2.1 percent of asking rents. The uptick in vacancies is largely attributed to a weakening labor market in health services and education, alongside the ongoing delivery of projects that broke ground during the pre-2022 low-interest-rate environment.

Despite the leasing slump, inventory growth continues with 1,736 units delivered in the first quarter and 10,218 units still under construction. Performance varies significantly by submarket; the South Boston/Seaport area remains the most expensive, with average rents of $4,500 and a 3.7 percent vacancy rate, while inner suburbs like Everett face higher vacancy levels at 10.2 percent. Developers are currently focused on lease-up strategies for new inventory, contrasting with national trends where absorption is beginning to outpace completions.