Sam’s Club, a division of Wal-Mart Stores Inc. (NYSE:WMT), abruptly posted closure notices on a number of stores across the country today.

Neither company has released any official statement, however an announcement on Sam’s Club’s official Twitter account reported that the company is closing 63 of its nearly 660 stores. The closings are expected to affect about 10,000 employees, according to various media reports.

Sam’s Clubs stores average 134,000 square feet, which would mean that closures could impact about 8.4 million square feet of ‘big box’ retail space. However, not all of it will end up vacant.

Sam’s Club tweeted that 10 of the closed locations are being converted into e-commerce fulfillment centers.

Walmart owns most of its Sam’s Club stores (591 out of 660), the others are leased. Sam’s Clubs stores in the U.S. post about $57 billion in revenue per year and account for about 12% of Walmart’s total sales.

Walmart reported that Sam’s Club comparable store sales were up 2.8% year-over-year and that foot traffic was up 3.6%

CoStar will continue to follow this story as more information becomes available.