Wal-Mart Stores, Inc. (NYSEWMT) warned investors Thursday that its stores are experiencing a slowdown that trickled over from late 2012 into early 2013.

The nation’s largest retailer blames the payroll tax hike and delay in income tax refunds on shoddy sales in the last two weeks of January 2012 and suggested that February 2013 sales had also been affected.

"February sales started slower than planned, due in large part, to the delay in income tax refunds. We began seeing increased tax refund check activity late last week in our stores, resulting in a more normalized weekly sales pattern for this time of the year," Bill Simon, Walmart U.S. president and chief executive officer, said in a statement.

While some experts suggest that Wal-Mart suppliers should be worried, CFO Charles Holley told CNN the stores have not yet changed any orders as a result of the eerie news.

Despite the reassurance, retail experts are projecting February to be a slow month, since Americans have recently been slammed with higher costs while also taking home less pay.

Gas prices hit a four-month high on Tuesday, with the national average for a gallon of regular at $3.73 -- 43 cents more than a month ago, according to the Automobile Association of America.

In addition to higher prices at the pump, workers earning the national average salary of $41,000 are receiving about $60 less on every monthly paycheck due to the expiration of payroll tax cuts just last month.

John Lawrence, an analyst at Stephens Inc., told CNN that Wal-Mart's customer base -- low-end to mid-scale shoppers -- is tapped out.

"This really eats away at discretionary spending, so people aren't going out and buying the TVs or the pair of jeans," he said. "There is no question that that stuff backs up in the supply chain."

Wal-Mart earned $5.61 billion, or $1.67 per share, from continuing operations in the fiscal fourth quarter, up from $5.19 billion, or $1.51 per share, a year earlier.

"We have high expectations for fiscal 2014, and I'm optimistic as I look ahead," Mike Duke, Wal-Mart Stores, Inc. president and chief executive officer, said in a statement.