Investing in one of these companies is obviously a massive risk, but it could also bring massive rewards. Biotech essentially lets you play at being a startup investor – picking companies that you think might make millions from drug sales later down the line. Potential profits for biotech companies are, naturally, massive. Their drugs have longer patent protection than other types of pharmaceuticals (12 years, rather than five), they’re significantly harder for rivals to copy, and their creators are top prospects for a multi-billion-dollar buyout by a big pharma company.

Because making biotech drugs is so time- and resource-intensive, firms need money to see them through their decade-plus of revenueless research. And with the risks often too high for bank managers’ loan books, companies look to investors instead. Biotechs tend to list shares on stock markets pretty early on in their lives – in 2018, Homology Medicines raised $166 million in its initial public offering, despite not having a single drug yet in clinical trials.

The takeaway: Drug development can take over a decade, and there’s no guarantee of a drug passing clinical trials.