CoinGlass data shows the Coinbase Bitcoin Premium Index has remained negative for 90 consecutive days from May 19 to August 16, most recently at -0.1066%, marking the longest negative streak on record. The index measures the Bitcoin price gap between Coinbase Pro and Binance. A persistently negative reading generally means Bitcoin is trading at a relative discount on Coinbase, which may indicate weaker U.S. buying demand or heavier selling pressure, but does not by itself prove sustained institutional outflows.