1 Boston Wharf Road

Potential layoffs at Amazon and deep cuts to Twitter’s workforce are adding to the headwinds faced by a Boston office market in the midst of a year-long retreat.

Amazon plans to lay off approximately 10,000 corporate and technology jobs beginning this week, in cuts that could affect its local workforces in Boston and Cambridge.

Twitter leased 44,000 square feet at Center Plaza in 2019, where it’s planning to terminate 55 employees effective Jan. 4, according to a letter to MassHire Department of Career Services cited by a Boston Globe report.

Approximately half of the social media giant’s 7,500 employees have been notified of layoffs since its $44 billion acquisition by Elon Musk in October.

Amazon leased its first local offices in Cambridge’s Kendall Square in 2013, and expanded into Boston in 2019, leasing 430,000 square feet at a new office tower at 111 Harbor Way in the Seaport District for 2,000 employees. The offices include divisions that specialize in its Alexa speech science technology, one of the divisions expected to be affected by the largest layoffs in the online retailer’s history according to a New York Times report.

Approximately 3,000 Amazon employees in the Alexa, Amazon Web Services, Amazon Robotics and Amazon Pharmacy divisions are  scheduled to occupy a 630,000-square-foot office tower at 1 Boston Wharf Road in the Seaport. The building is scheduled for completion in 2024.

Amazon leased another tech office in 2019 at One Cabot Road in Medford, also with a specialty in the Alexa program.

The cutbacks could add to already record-breaking listings of office sublease space, many in the volatile tech sector.

After laying off hundreds of employees during the summer months, online furniture retailer Wayfair has placed 400,000 square feet on the sublease market in multiple buildings, according to a Colliers brokerage report.

Drift, Cengage, GrubHub and LogMeIn listed nearly 1 million square feet of sublease space during the third quarter, Newmark said in its third-quarter Boston office market report.

And Reebok listed its Innovation and Design Building headquarters for sublease just five years after relocating from a Canton office park and touting the new location’s employee perks.

Boston’s office vacancy rate hit 15.4 percent in the third quarter, according to Colliers, and has nearly 688,000 square feet of negative absorption since January.