It was a classic case of buy the rumour, sell the fact.

In February this year, investors and analysts were concerned that the US economy was beginning to hot up, sparking fears that inflation would pick up and force the Federal Reserve to quicken its policy tightening. This, in turn, led to a surge in US government yields, which propelled the dollar to the year’s high against its peers a month later.

Fast-forward to the end of the first half of the year and inflation in the US is running at its fastest pace since the global financial crisis, but the dollar has weakened for two straight months after appreciating in the first quarter.

Most of the shift is down to US central bankers who rushed to reassure investors that they would keep conditions extremely accommodating, soothing the flare-up in Treasury yields and the dollar’s exchange rate.

As a result, analysts are pretty confident that Fed chair Jay Powell and his board will “look through” the rise in prices at the central bank’s rate-setting meeting next week, keeping the dollar on its current weakening path.

“The combination of steady Fed expectations and a broadening global economic recovery should allow recent dollar weakness [to] continue,” said Zach Pandl, co-head of foreign exchange strategy at Goldman Sachs, in a research note. He expected the euro to benefit the most against the US currency.

Still, some strategists cannot help but wonder whether they should stick to selling the fact, or if it is time to start buying the rumour — and the dollar — again. Despite inflation powering to above 5 per cent year on year, yields on 10-year Treasuries fell to their lowest in three months, in a counterintuitive reaction fuelled by the anticipation that policymakers will shrug off the building heat in the economy.

“Getting US inflation right may be the most important market call for the rest of the year,” said Athanasios Vamvakidis, global head of currency strategy at Bank of America in London.

A decision from the US central bank to keep its policy unchanged would allow the dollar to continue with its weakening path, but maybe not as much as traders anticipated at the beginning of 2021. Vamvakidis notes that currency markets are quietly pricing in less dollar weakness than at the start of the year, with the consensus view now calling for the euro to trade at around current levels $1.21 by the end of December rather than at $1.25.

“For now, high US inflation and a still dovish Fed keep real US rates highly negative and this supports the euro. The question is for how long this is sustainable if US inflation proves persistent,” he said, adding that the bank expected the euro to finish the year at $1.15.

Line chart of Dollar index (DXY) showing The dollar has weakened after first-quarter gains

There are signs that investors might be getting too relaxed. Options markets display little nervousness about the Fed meeting, and Mark McCormick, global head of currency strategy at TD Securities said negative bets on the dollar had begun to build up heavily again in recent weeks.

This adds to the risk of a sharp snapback in the currency’s exchange rate if the Fed does hint at tapering its asset purchases on Wednesday or before analysts expect.

“Don’t expect much more dollar weakness into the summer,” said McCormick.

There are also some offbeat signs that there is a risk of traders betting too heavily on the Fed’s commitment to keeping liquidity ample. Analysts at Standard Chartered noted that Treasury secretary Janet Yellen, a former Fed chair, mentioned the potential benefits of a higher interest rate environment twice in recent weeks.

John Davies, a US rates strategist at Standard Chartered, said that it was most likely that the Treasury chief was defending the Biden administration’s fiscal plans rather than criticising Fed policy, but it was highly unusual.

“It is still striking when the Treasurer of a public or private entity argues for higher borrowing costs,” said Davies.

Investors now expect the US central bank to start cutting its asset purchase amounts in the first quarter of next year, with an announcement pencilled in for potentially September, when the Fed meets for its annual symposium at Jackson Hole, according to Oliver Brennan, head of research at TS Lombard.

But while an earlier than expected announcement would cause some ructions, the real risk is that investors will have to start anticipating the timing of rate increases in the US, which could come sooner and harder than they anticipated.

“The taper sets the clock ticking for the first rate hike and real rates rise [and] big changes in Fed policy are rarely smooth-sailing,” said Brennan.