BlockBeats News, June 8th, according to Coinglass data, Coinbase's Bitcoin Premium Index has been in a negative premium for 21 consecutive days, currently at -0.0621%, with the purchasing power in the U.S. market remaining weak.Note: The Coinbase Bitcoin Premium Index is used to measure the difference between the Bitcoin price on Coinbase and the global market average price. A negative premium usually reflects a greater selling pressure in the U.S. market, a decrease in investor risk appetite, a rise in market risk aversion sentiment, or capital outflows.