New York CNN Business  — 

The number of Americans filing for their first week of unemployment benefits suddenly jumped last week to the highest level in more than two years.

The number of initial claims rose to 252,000 in the week ending December 7, an increase of 49,000 from the number of claims filed the week before, the Labor Department said Thursday.

That’s higher than the 213,000 claims economists had expected and marks the highest level since the week ending September 30, 2017.

Liz Ann Sonders, Charles Schwab Chief Investment Strategist, called it “a somewhat-uncomfortable pop up” in a tweet, but said it was “too soon to declare it an uptrend.”

Even though the pop in claims was notable, just one data point doesn’t make a trend. Last week’s data could be an outlier due to seasonal noise, given the timing around the Thanksgiving holiday on November 28.

The four-week average, which smooths out the Thanksgiving holiday week, was at 224,000.

“December and January are the biggest months for labor market turnover for the year so consequently there is excessive volatility in the claims,” Thomas Simons, senior money market economist at Jefferies, wrote in a note to clients.

“We should not read too far into this jump in claims,” he added.

The US labor market is still very strong, with the unemployment rate recently matching a 50-year low. That said, investors are keeping a close eye on erratic patterns in jobless claims.