There's no doubt that money can be made by owning shares of unprofitable businesses. For example, biotech and mining exploration companies often lose money for years before finding success with a new treatment or mineral discovery. Having said that, unprofitable companies are risky because they could potentially burn through all their cash and become distressed.

So, the natural question for Upstream Bio (NASDAQ:UPB) shareholders is whether they should be concerned by its rate of cash burn. In this article, we define cash burn as its annual (negative) free cash flow, which is the amount of money a company spends each year to fund its growth. First, we'll determine its cash runway by comparing its cash burn with its cash reserves.

When Might Upstream Bio Run Out Of Money?

A company's cash runway is calculated by dividing its cash hoard by its cash burn. When Upstream Bio last reported its March 2026 balance sheet in May 2026, it had zero debt and cash worth US$295m. Importantly, its cash burn was US$140m over the trailing twelve months. So it had a cash runway of about 2.1 years from March 2026. Arguably, that's a prudent and sensible length of runway to have. You can see how its cash balance has changed over time in the image below.

How Well Is Upstream Bio Growing?

Upstream Bio actually ramped up its cash burn by a whopping 68% in the last year, which shows it is boosting investment in the business. But the silver lining is that operating revenue increased by 45% in that time. On balance, we'd say the company is improving over time. While the past is always worth studying, it is the future that matters most of all. For that reason, it makes a lot of sense to take a look at our analyst forecasts for the company.

How Hard Would It Be For Upstream Bio To Raise More Cash For Growth?

Upstream Bio seems to be in a fairly good position, in terms of cash burn, but we still think it's worthwhile considering how easily it could raise more money if it wanted to. Issuing new shares, or taking on debt, are the most common ways for a listed company to raise more money for its business. Commonly, a business will sell new shares in itself to raise cash and drive growth. By comparing a company's annual cash burn to its total market capitalisation, we can estimate roughly how many shares it would have to issue in order to run the company for another year (at the same burn rate).

Since it has a market capitalisation of US$440m, Upstream Bio's US$140m in cash burn equates to about 32% of its market value. That's fairly notable cash burn, so if the company had to sell shares to cover the cost of another year's operations, shareholders would suffer some costly dilution.

Is Upstream Bio's Cash Burn A Worry?

On this analysis of Upstream Bio's cash burn, we think its revenue growth was reassuring, while its increasing cash burn has us a bit worried. Cash burning companies are always on the riskier side of things, but after considering all of the factors discussed in this short piece, we're not too worried about its rate of cash burn.

If you would prefer to check out another company with better fundamentals, then do not miss this free list of interesting companies, that have HIGH return on equity and low debt or this list of stocks which are all forecast to grow.

This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.