People shop at the Christmas Village in Philadelphia on Dec. 10. (AP Photo/Matt Rourke, file)

WASHINGTON (AP) — The U.S. economy grew at a surprisingly strong 4.3% annual rate in the third quarter, the most rapid expansion in two years, driven by consumers who continue to spend in the face of ongoing inflation.

U.S. gross domestic product from July through September — the economy’s total output of goods and services — rose from its 3.8% growth rate in the April-June quarter, the Commerce Department said Tuesday in a report delayed by the government shutdown. Economists surveyed by the data firm FactSet forecast growth of just 3% in the period.

As has been the case for most of this year, the consumer is providing the fuel that is powering the U.S. economy. Consumer spending, which accounts for about 70% of U.S. economic activity, rose to a 3.5% annual pace last quarter. That’s up from 2.5% in the April-June period.

A number of economists, however, believe the growth spurt may be short-lived with the extended government shutdown dragging on the economy in the fourth quarter, as well as a growing number of Americans fatigued by stubbornly high inflation.

A survey published by the Conference Board Tuesday showed that consumer confidence slumped close to levels not seen since the U.S. rolled out broad tariffs on its trading partners in April.

“The jump in consumer spending reminds me a lot of last year’s (fourth quarter),” said Stephen Stanley, chief U.S. economist at Santander. “Consumers were stretching. So, as was the case entering this year, households probably need to take a breather soon.”

The seemingly divergent paths between how consumers say they are feeling and how much money continues to be spent may be more evidence of what is known as a a ” K-shaped economy ” In that situation, the income of wealthier Americans is on the rise, due to stock market gains and growing investments, while lower-income households struggle with stagnant pay and higher prices.

“The latest data on household spending indicates continued strong gains in consumer spending, particularly on services,” wrote Michael Pearce, chief U.S. economist for Oxford Economics. “We think that reflects the K-shaped consumer recovery, with spending growth driven by older, wealthier households while those on low and more moderate incomes struggle.”

Tuesday’s GDP report also showed that inflation remains higher than the Federal Reserve would like. The Fed’s favored inflation gauge — called the personal consumption expenditures index, or PCE — climbed to a 2.8% annual pace last quarter, up from 2.1% in the second quarter.

Excluding volatile food and energy prices, so-called core PCE inflation was 2.9%, up from 2.6% in the April-June quarter.

Economists say that persistent and potentially worsening inflation could make a January interest rate cut from the Fed less likely, even as central bank official remain concerned about a slowing labor market.

“If the economy keeps producing at this level, then there isn’t as much need to worry about a slowing economy,” said Chris Zaccarelli, chief investment officer for Northlight Asset Management, adding that inflation could return as the greatest threat to the economy.

Another consistent driver in the U.S. economy, spending on artificial intelligence, was also evident in the latest data.

Investment in intellectual property, the category that covers AI, grew 5.4% in the third quarter, following an even bigger jump of 15% in the second quarter. That figure was 6.5% in the first quarter.

Consumption and investment by the government grew by 2.2% in the quarter after contracting 0.1% in the second quarter. The third quarter figure was boosted by increased expenditures at the state and local levels and federal government defense spending.

Private business investment fell 0.3%, led by declines in investment in housing and in nonresidential buildings such as offices and warehouses. However, that decline was much less than the 13.8% slide in the second quarter.