LONDON—Major cryptocurrency exchange Coinbase said it is buying a crypto futures exchange, FairX, as part of a move to offer crypto derivatives to traders in the United States. FairX, which was launched last year, is the operating name of LMX Labs. It sells futures products and is regulated by the U.S. Commodity Futures Trading Commission (CFTC). Coinbase said it wants to make trading of regulated crypto derivatives accessible to retail and institutional customers. “The development of a transparent derivatives market is a critical inflection point for any asset class and we believe it will unlock further participation in the crypto economy for retail and institutional investors alike,” it said in a blog post on Wednesday. Trading of cryptocurrency derivatives has grown rapidly since institutional investors have over the past 18 months begun to embrace digital coin trading, presenting big opportunities for platforms that offer future and options. Crypto derivatives volumes …