Image courtesy of MP Boston

A handful of high-profile leases at trophy office buildings couldn’t mask declining occupancy in Greater Boston’s office market during the third quarter.

The vacancy rate rose 0.5 percent to 14.9 percent, as downtown Boston office buildings had more than 1 million square feet of negative absorption, Newmark reported.

A recent surge in foot traffic and in-office work hasn’t translated into a revival of office leases, and tech companies offered nearly 1 million square feet of sublease space.

“A marked improvement in physical occupancies was noted after Labor Day, but tenants are still contending with some sluggishness in return-to-office momentum, and the long-term impact of flexible hybrid schedules is unclear,” Newmark’s third-quarter Boston office report said.

Large tenants including Wayfair, Drift, Cengage, GrubHub and LogMeIn offered 980,000 square feet of sublease space during the third quarter.

Two-and-a-half years since the initial COVID-19 outbreak emptied office buildings, major tenants continue to adjust their hybrid work policies.

Fidelity Investments this month expanded a pilot program in which all members of a work group are assigned to work three days in the office one week per month. But John Hancock Financial Services has scaled back its in-office requirements this year from three days per week to two.

Leasing activity at high-profile new and updated office towers has been strong, with the 1 million-square-foot One Congress fully leased and approximately half of the Winthrop Center skyscraper’s office space leased ahead of its completion in the first half of 2023. Eaton Vance finalized its 285,000-square-foot lease at One Post Office Square, which is undergoing renovations, while HarbourVest agreed to become the new anchor of One Lincoln which plans a $200-million capital improvement program.

Asking rents have remained steady at $44.32 per square foot across the 172.7 million-square-foot office market.

Vacancies rose 1 percent to 11.6 percent in Cambridge, and HubSpot and Akebia placed 400,000 square feet of sublease space on the market.