The big guy has delivered.

Walmart Inc. (WMT - Get Report) posted a strong second quarter on Thursday, Aug. 16, showing a revenue gain of 3.8% to $128 billion. Analysts polled by FactSet were expecting $125.9 billion.

The Bentonville, Arkansas company's U.S. same-store sales rose 4.5%, the strongest in a decade, on robust performance in grocery, apparel and seasonal goods. Analysts were expecting an increase of 2.3%.

Earnings per share came in at $1.29, 7 cents above the expected $1.22.

After the market opened, shares were up more than 10% to $99.29. In premarket trading, shares were up 10.9% to $100.02. Over the last 52 weeks, shares have ranged between $77.50 and $109.98.

Yet for all the glittering numbers, profitability remains a problem, according to one analyst.

"In terms of profit, this has been a quarter that Walmart would rather forget," Neil Saunders, managing director of GlobalData Retail, told TheStreet. "Operating income fell by 3.7%, a relatively weak outcome. At the net level, a $4.5 billion loss from the sale of 80% of Walmart Brazil pushed the company into the red by $861 million. Paradoxically, even if it looks bad, the net loss is forgivable as it is related to essential restructuring as Walmart moves its attention away from peripheral parts of its business. However, the decline in operating profit is more concerning as it reflects ongoing pressures from investing in lower prices, customer service, digital infrastructure and store refurbishments as well as increased labor and transportation costs. These pressures are unlikely to dissipate as the year progresses."

In addition, the company raised its guidance, saying it now expects full-year net sales to rise 2%, U.S. comps to jump 3%, and earnings of $4.90 to $5.05 a share, up from previous guidance of $4.75 to $5.

Walmart said its U.S. e-commerce business grew by 40% in the fiscal second quarter.

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