Cryptocurrency-custody firm NYDIG says hundreds of banks have enrolled in a program that will allow them to offer to their customers the ability to buy, sell, or hold bitcoin (BTC-USD).Bitcoin rises 6.3% in the past 24 hours to ~$57.2K.Most bitcoin adopters have used fintech apps like Robinhood (RBNHD), PayPal ([[PYPL]] -0.1%), Square ([[SQ]] +2.6%), and Coinbase ([[COIN]] +1.7%) to invest in bitcoin. And recently, some of the biggest banks have announced plans to allow their wealth management clients to buy, hold, or sell the cryptocurrency.The crypto-custody firm teamed up with bank tech firm FIS ([[FIS]] -0.4%) to introduce the offering.NYDIG is in talks with some of the biggest U.S. banks regarding the product, Patrick Sells, head of bank solutions at NYDIG, told CNBC. Many of the banks that have already signed up are smaller institutions.“This is not just the banks thinking that their clients want bitcoin, they’re saying `We need to do