"They raised the longer run 'dot plot' for the first time after what seemed to be an inexorable decline," said Robert Rennie, head of market strategy at Westpac. "The US dollar likes it; bonds do not."

Currency and bond markets had become so used to dovish surprises from the Fed that even a mildly hawkish shift was enough to cause some whiplash.

Even so, compared with last year, the US dollar had more speculative momentum in its favour going into the Fed meeting. Net dollar longs that had built up rapidly in November 2015 were scaled back ahead of the rate hike. This year, a more modest build-up began in November but persisted into December, reflecting greater confidence in the dollar rally.

Those bets on the US dollar could build with a more aggressive Fed. Krishna Guha, the vice chairman of Evercore ISI in Washington who previously worked at the New York Fed, says the central bank's clearly hawkish turn is "a recipe for more US dollar strength".

Rennie at Westpac also sees a sustainable rally.

"Markets don't like fatter, longer tails, and we got them in the Fed projections for 2018-19," Rennie said. "The dollar should remain well supported into year's end."