WeWork Inc. shares plummeted more than 25% in extended trading after saying there’s “substantial doubt” about its ability to continue operating. The company cited sustained losses and canceled memberships to its office spaces.

The co-working business will focus over the next 12 months on reducing rental costs, negotiating more favorable leases, increasing revenue and raising capital, WeWork said in a statement Tuesday.

The warning comes mere months after WeWork struck a deal with some of its biggest creditors and SoftBank to cut its debt load by around $1.5 billion and extend other maturities. Its bonds trade at deeply distressed levels. The company’s 7.875% unsecured notes due 2025 last changed hands for 33.5 cents on the dollar, according to data from Trace.

Just a few years ago, WeWork was one of America’s most valuable startups. Venture capitalists fueled its rise with billions of dollars to rent up real estate around the world and lease it back to workers. The co-founder Adam Neumann led a disastrous attempt at an initial public offering in 2019, resulting in his ouster as chief executive officer and necessitating a financial rescue from its major backer, SoftBank Group Corp.

The Covid-19 pandemic dealt another blow. WeWork’s office locations, which emptied out during the early months of the health emergency, were showing slow progress toward filling back up over the last year. But the recovery appears so far to be unsustainable. WeWork said occupancy dropped in the second quarter compared to the previous quarter.

The New York-based company has also been weathering a change in leadership. Sandeep Mathrani, who took over as CEO in early 2020, left in May to become a partner at private equity firm Sycamore Partners. WeWork currently has an interim CEO. On Tuesday, WeWork said three of its independent board members are being replaced by four new board members.

--With assistance from Claire Boston.

(Updates with shares and context starting in the first paragraph.)