HYM Investment Group managing partner Tom O'Brien watches construction crews put the finishing touches on a large amenity terrace on the 11th floor of HYM's One Congress office building on Sept. 11, 2023. The building officially opened Sept. 14. Photo by James Sanna | Banker & Tradesman staff

A recent analysis by researchers at commercial brokerage JLL has concluded that a high level of amenities is the key difference between buildings that kept or gained tenants over the last four years, and those that lost tenants.

U.S. office buildings with 10 or more amenities plus one signature amenity like a roof terrace or a full-service fitness center have weathered office tenants’ broader downsizing trend since the pandemic. Buildings meeting that definition collectively gained 23 million square feet of net absorption since the second quarter of 2020, when the pandemic began. At the same time, JLL found, the rest of the nation’s urban class A office properties have lost more than 50 million net square feet of office occupancy.

“Differentiation and quality are the primary drivers of rent premiums gained through amenitization,” Jacob Rowden and Elena Lanning wrote.

Roof terraces performed the best, adding a 5.2 percent premium to rents in buildings that had them over the rest of their same submarket’s typical class A rent, followed by a courtyard with outdoor seating at 3.5 percent.

A fitness center with showers was the next-most impactful amenity, adding a 2.9 percent rent premium, followed by two “green” amenities: LEED certification (2.8 percent premium) and EV charging stations (2.2 percent premium).

Owners of Boston’s newest trophy office buildings – as well as owners of older trophy buildings with new renovation plans and even some tenants – are putting amenities front and center in their marketing, from an acre of indoor and outdoor lounge space at One Congress, to a health clinic at One Post Office Square to a food hall curated by a Michelin-starred chef at Winthrop Center.