Last week, a top U.S. banking regulator warned of growing risks as banks start to capitalize on the popularity of cryptocurrencies to offer related services to clients. Here is how some of the biggest banks operating in the United States have gotten involved in crypto: Custody Services Bank of New York Mellon announced in February 2021 that it would hold, transfer and issue bitcoin for asset management clients, one of the first announcements of its kind for a major Wall Street bank. The launch is expected later this year. Clients will be able to store bitcoin and ether, the two largest cryptocurrencies, in BNY Mellon crypto wallets, which will be created in partnership with crypto infrastructure company Fireblocks. U.S. Bancorp went live in October with bitcoin custody services. Bitcoin company NYDIG is acting as a sub-custodian for the bank. The services are geared toward institutional investment managers with private funds. …