Four million. That’s roughly how much bitcoin is circulating freely right now, blockchain data show. The number has been getting a little smaller with each passing month over the last year. 

It’s the assessment of Glassnode, an analysis firm that tracks blockchain data. The pattern suggests that the ever-decreasing supply of bitcoin available to buy and sell might lead to a price surge as more institutional investors embrace the largest cryptocurrency as an investment.

Bitcoin’s “liquid supply change” – the amount by which the number of coins in circulation has changed over the prior 30 days – has been negative for most of the past year, according to Glassnode: