European and US stocks treaded water Wednesday following data showing accelerating inflation, while the dollar retreated as the Federal Reserve chief maintained a dovish stance on monetary policy.

Producer price index data showed an increase of 7.3 percent for the 12 months ended in June, its largest-ever yearly jump since the Labor Department began tracking it more than a decade ago.

The report comes on the heels of Tuesday's consumer price data that also showed a big rise, prompting an acknowledgement from Fed Chair Jerome Powell that inflation was stronger than the Fed was hoping to see and will remain "elevated" in coming months.

But Powell stuck to his guns on policy, vowing to continue to provide stimulus until the recovery is complete

The US economy still has "a long way to go" to return to full employment following the Covid-19 pandemic, Powell said in his semi-annual testimony to Congress.

The Fed "will ensure that monetary policy will continue to deliver powerful support to the economy until the recovery is complete," he said.

However, the dollar, which had rallied in anticipation that Powell might articulate a timeframe to taper stimulus, pulled back.

Britain's annual consumer price index rate meanwhile jumped to 2.5 percent in June, the highest since August 2018, data showed Wednesday.

"Inflation is getting hotter and hotter," said Markets.com analyst Neil Wilson.

"The Fed and Bank of England will hope that the hot readings are a summer heatwave driven by parts of the economy that were essentially shut down last year."

Investors are on red alert over global inflation as pent-up demand and galloping prices could force policymakers to raise interest rates earlier than thought, hindering the post-Covid economic recovery.

The counterargument is that recent price increases constitute "peak inflation" and will soon ebb.

London stocks fell by 0.5 percent. Stock indices in Frankfurt and Paris were unchanged, with many French traders away for the Bastille Day holiday.

Asian markets fell earlier in the day, and oil prices pulled back after US data showing weakening of gasoline demand.

Investors will be waiting to hear Fed Chair Jerome Powell's testimony for indications over the direction of the US central bank's policy following a surprise surge in inflation
Investors will be waiting to hear Fed Chair Jerome Powell's testimony for indications over the direction of the US central bank's policy following a surprise surge in inflation AFP / Daniel SLIM

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