In this Wednesday, Nov. 22, 2012, photo, Eva Cevallos with her eleven-month daughter, Quinn, shop during the Thanksgiving Pre-Black Friday event at the Walmart Supercenter store in Rosemead, Calif. Wal-Mart Stores Inc. offered a weak business outlook Thursday, Feb. 21, 2013, as new economic challenges for its low-income U.S. shoppers start to take a toll. (AP Photo/Damian Dovarganes)

NEW YORK (AP) -- As the fortunes of many Americans go, so goes Wal-Mart, so goes the economy.

Even as the world's largest retailer on Thursday reported an 8.6 percent rise in fourth quarter profit during the busy holiday shopping season, it offered a weaker forecast for the coming months. The problem? The poor and middle-class Americans Wal-Mart caters to — and who are big drivers of spending in the U.S. — are struggling with rising gas prices, delayed income tax refunds and higher payroll taxes.

Melanie M. Burkhardt, a mother of two teenagers who shops at Wal-Mart, is one of those people. Burkhardt, a Waycross, Ga., resident, said she's been hit with a double whammy: the payroll tax hike, which has cut her household monthly income by $260, and higher gas prices.

"We had to do a flip on our budget," said Burkhardt, a legal assistant who plans to cut back on her trips to Wal-Mart. "This is money we used for things like going to a movie or splurging at Olive Garden. Not anymore."

It's widely known that Americans in the lower income brackets continue to struggle even as higher earners benefit from improved housing and stock markets, but Wal-Mart's results signal that matters may be getting worse for the nation's poor and middle-class. Wal-Mart is the latest in a string of big-name companies from Burger King to Zale to say those Americans are being squeezed by new challenges. But since Wal-Mart accounts for nearly 10 percent of nonautomotive retail spending in the U.S., it is a bellwether for the economy.

"Wal-Mart moms are the barometer of the U.S. household," said Brian Sozzi, chief equities analyst at NBG Productions who follows Wal-Mart. "Right now, they're afraid of higher taxes and inflation."

Indeed, while wealthier households have seen their stock portfolios grow, poor and middle-class Americans have struggled to regain their financial footing since the recession ended more than 3 ½ years ago.

Stocks have roughly doubled since June 2009. Dividends and capital gains from stocks, which disproportionately benefit higher-income Americans, are taxed at lower rates compared with ordinary income

And while incomes for most Americans have failed to keep pace with inflation since the recession, that's been particularly true for middle and lower-income earners.

Median household income, adjusted for inflation, fell 1.5 percent to $50,054 in 2011 compared with 2010, the latest periods for which figures are available, according to the Census Bureau. That was down 8.1 percent from 2007, just before the recession began. (The median is the point halfway between the highest and lowest levels.)

But lower and middle-income households fared worse: The share of overall income earned by the bottom 80 percent of households shrank in 2011, while the income for the top 20 percent grew. And in 2012, inflation-adjusted hourly pay barely rose, inching up 0.3 percent.

Another hurdle for lower- and middle-income Americans has been the jump in gas prices since mid-January. The average price for a gallon of gas rose 47 cents in the past month to $3.78 on Thursday, according to AAA.

Tax changes also have hit the nation's lowest earners especially hard. On Jan. 1, Social Security payroll taxes rose 2 percentage points after a temporary tax cut expired. That sliced about $1,000 from the take-home pay of a household earning $50,000. Since the Social Security tax is levied against income only up to $114,000, it disproportionately affects middle- and lower-income households.

An even larger challenge for many lower-income Americans has been the government's delay in processing income taxes and paying refunds. That's because income tax rates weren't set until a last-minute deal between the White House and Congress on Jan. 1. So the IRS pushed back the start of tax-filing season to Jan. 30, two weeks later than usual.

As a result, by Feb. 14 the government had paid only $55 billion in refunds, down from $77 billion at the same time last year, according to an estimate by UBS. That drop of $22 billion is more than twice the impact of the higher payroll tax. Refunds have accelerated recently and will eventually be paid out, but the impact still can be felt by many taxpayers: About 78 percent of taxpayers receive refunds, and the figure rises to 82 percent for those reporting income below $50,000.

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