What to know about Cathie Wood's proposed bitcoin ETF, 'ARKB'

Cathie Wood's Ark Invest is creating a bitcoin exchange-traded fund in partnership with 21Shares. The SEC last week again postponed a decision to approve the first bitcoin ETF. Wood, a longtime bitcoin bull, has been buying up proxies for the digital asset in names such as Coinbase and Grayscale Bitcoin Trust. CNBC's Kate Rooney reports.