As Colorado celebrated a year of cannabis legalisation, Founders Fund, a venture-capital firm with $2 billion in assets that backed Facebook, has announced an investment in Privateer Holdings, a marijuana outfit behind names such as Leafly and [Bob] Marley Natural. Four states and Washington, DC, have now legalised recreational weed. A further 21 allow medical consumption under differing restrictions. Legal recreational and medical sales amounted to $2.6 billion last year, most of them in California and Colorado. That is just 6% of the estimated $40 billion still going to criminals (over $200 billion a year is spent on tobacco and alcohol). Cannabis venture capital was a tiny $104m in 2014 and opportunities remain limited because of federal restrictions. Full legalisation is perhaps five to ten years away. But investors beware: when it comes, the price of weed may fall.