Fairfield County office vacancies hit an all-time high as leasing activity has plummeted during the pandemic, according to a brokerage report.

Cushman & Wakefield said the countywide vacancy rate hit 30.9 percent in the first quarter, while asking rents fell to $0.53 below the five-year quarterly average of $33.16 per square foot.

Leasing activity has plummeted over the past year as companies take a wait-and-see attitude toward future space needs and return-to-the-office strategies. Lease transactions declined 33.9 percent in the first quarter compared with the same period in 2020, Cushman & Wakefield said.

The one bright spot in Fairfield County appears to be the downtown Greenwich submarket, where several New York City-based financial companies have set up suburban offices. Those transactions accounted for 32 percent of all leasing activity in Fairfield County during the first quarter, according to CBRE’s first-quarter MarketView report.

A majority of the leases and expansions in Greenwich since the beginning of the pandemic were inked by New York City firms. During the most recent quarter, Manhattan-based Elliott Capital Management, signed a 40,000-square-foot sublease at 600 Steamboat Road in Greenwich, while iCapitalNetworks expanded by 27,000 square feet at 2 Greenwich Plaza.

Stamford’s north submarket has the highest vacancy rate in the county at 29.3 percent, according to CBRE.