The dollar has been mired in its worst slump in a decade, battered by political drama in Washington and shifting bets on central bank policy. Managers of $3 trillion say the carnage has gone on long enough.

Mellon Capital Management Corp., State Street Global Advisors and UBS Asset Management are wagering that the greenback will recoup some of its 9% slide in 2017 as traders embrace a scenario that was all but written off a few weeks ago: a December rate hike by the Federal Reserve. That view gained traction Wednesday after policy makers stuck to their forecast for another increase this year. The dollar surged on the announcement.

The trajectory of the dollar has far-reaching implications for financial markets. A sustained rebound may erode export earnings at U.S. companies and squelch rallies in gold and emerging-market assets, all of which benefit from a weaker greenback. After a six-month slide in the world's reserve currency, its longest since 2007, the dollar is due for a respite in the eyes of some asset managers.