An exchange-traded fund betting on U.S. dollar gains is shrinking rapidly as the currency’s outlook darkens. Total assets in the Invesco DB US Dollar Index Bullish Fund (ticker UUP) have dwindled to $337 million, down from a peak of $1.04 billion in April, according to data compiled by Bloomberg. More than $68 million exited the ETF on Monday in its biggest single-day outflow in a month. Investors have become increasingly wary as Wall Street’s warnings on the dollar grow louder. Citigroup Inc. strategists said this week that the currency could plunge as much as 20% in 2021 should Covid-19 vaccines turn out to be ... (full story)