This week’s blockbuster IPO of Circle, a leading issuer of stablecoins, shows how crypto is increasingly going mainstream. Here’s how to invest.

Shares of stablecoin issuer Circle Internet Group Inc. stayed hot in its second session of trading on Friday and helped sparked gains in stocks in other cryptocurrency-related companies.

What exactly does Circle do, and why did it decide to move its headquarters from downtown Boston to lower Manhattan late last year? Here are six things to understand about the company, which manages a "stablecoin" called USDC.