EUO provides inverse 2x daily exposure to the USD/EUR cross. Due to its daily rebalance, the effects of compounding and path dependency weigh in on the long-term returns of the fund, which means that investors holding the fund longer than a day may not attain -200% exposure. As a result, EUO may not be suitable for those looking for predictable, long-term returns. Also keep in mind that EUO references the EUR/USD cross rate as reported by Bloomberg at 4 pm ET.