Inventories were up 8.2 percent from April 2011, the department said, while the March estimate, released a month earlier, was revised higher by $100 million to $480.5 billion, the department said.
The figures are adjusted for seasonal variations, but not for price changes.
Wholesale sales for April, also adjusted seasonally but not for prices, rose 1.1 percent month-to-month and 6.8 percent from a year earlier, reaching $415 billion. March's sales estimate was revised down by 0.1 percent or $500 million.
The inventory-to-sales ratio -- reflecting how many months it would take a company to deplete its inventory at the current sales pace -- came in at 1.17, unchanged from a month earlier and slightly higher than the ratio a year earlier, which stood at 1.15.
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