A shopping cart is seen in a supermarket in Manhattan, New York City
U.S. consumer sentiment falls in October Reuters

Consumers in the U.S. are the least optimistic in five months as concerns about inflation affected views of their personal finances.

A preliminary reading of the University of Michigan's Consumer Sentiment Index dropped to 63 from a final reading of 68.1 in September. It's the lowest level since May, when the index was at 59.2. The number stayed further from the near-two-year high of 71.6 in July.

According to the survey, assessments of personal finances fell 15% from September. Consumers' sentiment of business conditions in one year fell 19% but remained little changed for the long-run, which suggests consumers don't expect worsening economic conditions to persist, the report said.

Inflation in the 12 months through September was 3.7%, the same level of August, the Bureau of Labor Statistics said Thursday. Prices rose 0.4% from August. The pressure came mainly from higher rents and gas prices.

Annual U.S. inflation continues to be well above the Federal Reserve's target of 2%. Markets expect the Fed to increase its benchmark interest rate one more time this year from the current range of 5.25% to 5.5%.

Concerns about consumer behavior were flagged by JPMorgan, Citigroup and Wells Fargo on Friday in their third-quarter earnings results. Although the three big U.S. banks reported higher profits for the period, they warned of a slowdown in spending.

JPMorgan Chief Executive Officer Jamie Dimon said in a statement that U.S. consumers and businesses are still healthy, but "consumers are spending down their excess cash buffers."

Citi said a deceleration in spending indicates an "increasingly cautious consumer." Wells Fargo also pointed to a deterioration of credit.