Based on numerous conditions: CFTC euro dollar extreme values (long crowed), CFTC dollar index extreme values (short crowed), german bonds 2y/10y vs us 2y/10y bonds spreads, american and europe inflation divergences (5y5y swaps), quantitative tightening (america fed hikes) vs esasing (europe ECB bond purchase), trump fiscal dollar multinational repatriation (buying dollar and sell other currencies) ...