The office-leasing startup WeWork plans to raise more funding through a $500 million bond sale, according to the Financial Times.

It's the first time the company is raising money from debt investors after it raised billions in venture capital from backers such as SoftBank.

WeWork disclosed startling underlying numbers for its business in its bond-sale documents, such as that it owes $18 billion in rent.

The company's revenue rose dramatically last year, but its costs rose faster.

WeWork, the office-leasing startup, is looking to raise more cash through its first bond sale, despite already raising billions in venture funding.

WeWork is planning to sell $500 million (£358 million) in high-yield notes, per reports from the Financial Times and Bloomberg this week.

And bond documents reviewed by the two publications reveal some startling numbers — here's a summary:

WeWork owes $18 billion in rent. The company has more than 14 million square feet of office space, with suitably massive lease obligations, though WeWork has the option of closing locations if it can't pay those bills.

The company has more than 14 million square feet of office space, with suitably massive lease obligations, though WeWork has the option of closing locations if it can't pay those bills. WeWork is burning cash. Revenue from memberships more than doubled last year, to $822 million, but expenses also more than doubled, to $1.81 billion. Net losses came to $934 million, according to Bloomberg.

Revenue from memberships more than doubled last year, to $822 million, but expenses also more than doubled, to $1.81 billion. Net losses came to $934 million, according to Bloomberg. It isn't really about tech startups. About 20% of WeWork's occupants are in financial, legal, and business services, while 15% work in software.

About 20% of WeWork's occupants are in financial, legal, and business services, while 15% work in software. A focus on bigger companies means higher occupancy rates. Filling desks — and keeping them filled — is an important metric for WeWork, which says it has done so with 81% of them, higher than its minimum requirement of 60% occupancy to cover costs.

Filling desks — and keeping them filled — is an important metric for WeWork, which says it has done so with 81% of them, higher than its minimum requirement of 60% occupancy to cover costs. Like other tech CEOs, Adam Neumann controls the company. He has more than 65% of the voting power.

WeWork has expanded rapidly, helped by the $4.4 billion it raised last year from its main backer, SoftBank. According to its bond documents, the company had 220,000 members as of March and 251,000 desks across 234 locations.

Skeptics worry that WeWork is overly exposed to market shifts that could affect its occupants and their willingness to pay membership fees. But the optimistic view is that WeWork's leases eventually generate more cash than its costs as occupancy rates rise and the company gets its upfront spend on the "fit-out" for new properties out of the way.