Washington — Consumer prices jumped more than expected last month, the Labor Department said on Wednesday, adding to the fear of higher inflation that has roiled financial markets in recent days.

The consumer price index increased 0.5 percent in January, up from 0.2 percent the previous month and well above analyst estimates. The annual inflation rate was 2.1 percent, the same as it was for the 12 months that ended on Dec. 31.

Higher prices for energy, particularly gasoline, as well as for apparel fueled the sharp increase in the index, which recorded its largest most month-over-month jump since September.

Although the consumer price index is not the most important measure of inflation, its release on Wednesday took on outsized importance as investors scrambled for any new details about the direction of the economy.

The report roiled stocks again on Wednesday after three straight positive sessions.

Futures for the Dow Jones industrial index were up about 150 points before the Labor Department released the consumer price index. The higher-than-expected inflation led those Dow futures to drop significantly.

The Dow opened down more than 100 points but turned positive, and then bounced between small gains and losses in early trading.

The broader Standard & Poor’s 500 index and technology-heavy Nasdaq composite showed modest gains.

Concerns that inflation is accelerating, which could lead to higher interest rates, caused last week’s severe stock market declines. And the new data on consumer prices rekindled those concerns on Wednesday even though the annual inflation rate held steady.

“January inflation did come in hot and higher than expected, there’s no doubt about it … but it’s not too alarming,” said Scott Anderson, chief economist at Bank of the West.

But he noted the Commerce Department reported on Wednesday that retail sales fell unexpectedly in January, posting their biggest drop in nearly a year. Sales fell 0.3 percent after a flat December, as Americans cut back on purchases of automobiles and building supplies.

Anderson said the disappointing retail sales data indicate that inflationary pressures from higher consumer spending haven’t developed, despite many workers receiving one-time bonuses linked to the tax cut legislation enacted late last year,

“The narrative doesn’t hold together if inflation is being driven up by demand, the strengthening of the labor market and wage growth, because it wasn’t visible in the retail sales data,” he said.

The so-called core consumer price index, which excludes often-volatile food and energy costs, increased 0.3 percent in January. That was up from 0.2 percent the previous month.

The annual rate for the core consumer price index held steady last month at 1.8 percent.

The Federal Reserve has an annual inflation target of 2 percent, a level that indicates rising wages but not an overheating economy.

Inflation has been stubbornly low throughout the recovery from the Great Recession, which has helped keep interest rates at historically low levels and made stocks an attractive investment option.