ETFs tracking the U.S. dollar are gaining investor attention as the greenback faces increased pressure amid increasing global trade tensions and indications of a weakening U.S. economy. As sentiment turns bearish at a record pace, ETFs such as Invesco DB U.S. Dollar Index Bullish Fund UUP -0.90% are becoming crucial tools for investors trying to deal with the volatility. The most popular dollar ETF is UUP, which provides exposure to the greenback versus a basket of currencies including the euro, yen, and pound. It’s constructed to profit when the dollar rises — but has underperformed in recent days as bearishness...