The troubles faced by co-working titan WeWork are darkening the outlook for the world¡¯s largest business hubs, where rising office vacancies are already heaping pressure on investors set to refinance big-ticket mortgages next year.

Media reports on Wednesday suggested the New York-listed flexible workspace provider ¡ª once privately valued at $47 billion ¡ª was weighing a petition for bankruptcy next week.

Backed by Japan¡¯s SoftBank, WeWork aimed to revolutionize the office market by taking long leases on large properties and renting the space to multiple smaller businesses on more flexible, shorter arrangements.