The weaker dollar is failing to spur bitcoin's (BTC) usual rally, and J.P. Morgan Private Bank explains the unexpected behavior as a window into the nature of the U.S. currency's decline. The Dollar Index (DXY), which measures the greenback against a basket of peers, has dropped 10% in the past year. Bitcoin, which historically gains during periods of dollar weakness, lost 13% in the same period, CoinDesk data show. The CoinDesk 20 index (CD20), a measure of the largest digital assets, fell 28%. The dif ...