WASHINGTON (BLOOMBERG) - Prices paid by United States consumers rose in September by more than forecast, resuming a faster pace of growth and underscoring the persistence of inflationary pressures in the economy.

The consumer price index (CPI) increased 0.4 per cent from August, according to Labour Department data released on Wednesday (Oct 13). Compared with a year ago, the CPI rose 5.4 per cent, matching the largest annual gain since 2008.

Excluding the volatile food and energy components, so-called core inflation rose 0.2 per cent from the prior month.

A combination of unprecedented shipping challenges, materials shortages, high commodities prices and rising wages have sharply driven up costs for producers.

Many have passed some portion of those costs along to consumers, leading to more persistent inflation than many economists - including those at the Federal Reserve - had originally anticipated.

The pick-up in price growth seen last month reflected higher food and shelter costs. Meantime, measures of used cars and trucks, apparel and airfares cooled.

US stocks opened higher while the yield on the 10-year Treasury declined. The median estimate in a Bloomberg survey of economists called for a 0.3 per cent monthly gain in the overall measure and a 0.2 per cent advance in the core rate.

The CPI data reflects cross-currents in the economy. Hotel fares fell, reflecting the impact of the Delta variant on travel, but inflation is broadening out beyond categories associated with reopening. That's "worrisome" from the Fed's perspective, Bloomberg Economics said in a note.

Higher home prices are now starting to filter through in the data. Rent of primary residence jumped 0.5 per cent, the most since 2001, while a measure of homeowners' equivalent rent posted the biggest gain in five years.

Shelter costs, which are seen as a more structural component of the CPI and make up about a third of the overall index, could prove a more durable tailwind to inflation.

The report will likely reinforce the Fed's inclination to soon start tapering its asset purchases, especially as the supply-chain challenges plaguing businesses show little signs of abating.

"Between now and the medium term, investors need to be braced for data which will appear, at least, to threaten the 'transitory' story," Mr Ian Shepherdson, chief economist at Pantheon Macroeconomics, said in a note.

Following the data, overnight interest rate swaps briefly priced in a September 2022 rate hike before pushing it out to November.

American consumers are also experiencing higher prices for new vehicles and household furnishings and supplies, which increased by a record 1.3 per cent, the report showed. And looking ahead, elevated energy prices are set to take an additional bite out of workers' pay cheques.

A New York Fed survey out on Tuesday showed US consumers' expectations for inflation continued to rise in September, with one-year and three-year expectations accelerating to record highs.

While wages have strengthened in recent months, higher consumer prices are eroding Americans' buying power.

Inflation-adjusted average hourly earnings rose 0.2 per cent in September from a month earlier, but are down 0.8 per cent from a year ago, separate data showed on Wednesday.

To help offset higher prices, more than 64 million American retirees collecting Social Security benefits will see a 5.9 per cent increase in their monthly payments in 2022, the Social Security Administration said on Wednesday.

"Come January, beneficiaries can expect to see one of the largest increases in monthly benefits not only in their time on the programme, but in the programme's past 40 years," said Mr Jason Fichtner, chief economist at the Bipartisan Policy Centre.