Inflows into cryptocurrency funds and products, at $4.2B, are already in record territory before the quarter is even over, according to CoinShares data.That surpasses the previous record of $3.9B in Q4 2020, which brought total inflows for the year to $6.7B.Bitcoin, the world's largest cryptocurrency in terms of market cap, accounted for the largest share of flows, at $3.3B, while ethereum came in second with $731M.The more investors flock into cryptocurrency, though, the more regulators may take notice. That may slow the growth rate some. "The potential for more scrutiny and tighter regulation remains the biggest headwind for bitcoin," said Jesse Cohen, senior analyst at Investing.com.Cryptocurrency assets under management also grew to $55.8B, vs. $37.6B last year, according to CoinShares.Grayscale Bitcoin Trust ([[GBTC]] -2.9%) is the largest digital currency manager at $43.73B in assets, followed by CoinShares with almost $5B in assets.