200 Clarendon in Boston's Back Bay. File photo

Slowdowns in leasing, potential unpaid rents and delays in new tenant move-ins because of construction moratoriums are casting doubt on Boston Properties’ anticipated revenues for the rest of 2020, executives said.

The class A office REIT withdrew its previously-issued 2020 earnings guidance, citing the effects of the COVID-19 pandemic on its tenants. In January, Boston Properties projected funds from operations of $7.47-$7.65 per share, an 8-percent increase, and earnings of $5.91-$6.09 per share.

“We believe there are too many variables to provide prudent guidance at this time,” Chief Financial Officer Michael LaBelle said during a call with analysts on first-quarter earnings.

Boston Properties reported first-quarter funds from operations of $284.1 million, up 7 percent from the first quarter of 2019. Revenues grew 4 percent to $752.6 million.

The company said it’s collected 90 percent of rent payments due April 1 from its retail and office tenants, including 95 percent of office tenants. Nearly 72 percent of the office portfolio is comprised of tenants in the financial services, tech and life science and legal industries. Unpaid rent collections were concentrated in the coworking, manufacturing, retail and consumer product industries, executives said.

The effects of social distancing will have a mixed effect on demand for office space, CEO Owen Thomas predicted, as tenants prepare for the eventual lifting of shelter-in-place orders.

“Our customers with dense layouts are removing work stations and will return to work in a less dense environment,” Thomas said. “Some users will have a portion of their employees work remotely, and some will require more space.”

Boston Properties has formed a task force to prepare properties for the turn of the bulk of its tenants, with an eye on new processes, technology and communications. The bulk of the portfolio is located in high-rent coastal markets including Boston, New York, San Francisco, Los Angeles and Washington, D.C.

Two potential speculative projects in San Francisco and San Jose that Boston Properties had considered launching on speculation are now on hold, Thomas said: the 820,000-square-foot 4th and Harrison project in San Francisco and the 1.1 million-square-foot Platform 16 office campus in San Jose.