Coinbase's Bitcoin premium index has remained negative for 37 consecutive days, according to Coinglass data as of February 21. The index, currently at -0.0523%, indicates a longer duration of negative premium than the approximately 30 days observed during the "1011 crash." This index measures the price difference between Bitcoin on Coinbase and the global market average, with a negative premium suggesting stronger selling pressure in the U.S. market. The persistent negative premium reflects a decline in investor risk appetite and a rise in risk-off sentiment, potentially indicating capital outflows from the U.S. market. This trend highlights ongoing market dynamics and investor behavior in response to broader economic conditions.