Amazon.com Inc. showed that even it is not free of site outages, as its e-commerce site went offline for about 20 minutes last Thursday.

The outage, on which Amazon has not commented, may have cost sellers on Amazon about $200,000 in business-to-business sales and more than $3 million in retail sales, according to multiple outside estimates.

More than 20,000 businesses ranging in size from small organizations to Fortune 500 companies purchase products through the Amazon Business B2B marketplace, Amazon says. The gross transaction value of products sold over Amazon Business is projected at $5.2 billion in 2016, up 30% from $4 billion last year, says Scot Wingo, CEO of ChannelAdvisor Corp., which helps companies sell through e-marketplaces. Based on that figure, a 20-minute outage could have cost sellers on Amazon Business about $200,000. Amazon.com Inc. did not return requests for additional information regarding the outage. Another estimate by Internet Retailer puts the loss in retail sales at about $3.75 million.

Not all sellers were affected by the outage, however. Neal Brenner, founder and president of N2Surplus Inc., says he didn’t notice any loss of sales at the distributor of surplus products ranging from office supplies and eyeglass frames to industrial valves and materials for scientific laboratories. N2Surplus sells through Amazon and other marketplace sites as well as through its own site at N2Surplus.com.

David Phipps, CEO of Orbital Tracking Corp., says the manufacturer and distributor of satellite tracking devices hasn’t experienced a loss of sales either. “Our business on Amazon.com remains brisk,” he says. “The company also hasn’t received any customer complaints about it either.” Orbital Tracking sells through its own B2B e-commerce sites, GlobalTeleSat.co.uk and OrbitalSat.com, as well as on consumer-facing Amazon sites in the United States, Japan, Italy, France, Spain, Germany and the United Kingdom. It will launch a storefront on Amazon Business sometime during its second fiscal quarter.

Amazon Business ranks No. 37 in the B2B E-Commerce 300, a ranking of companies by their annual B2B web sales, and Amazon.com is No. 1 in the Internet Retailer Top 500, a ranking of companies by their annual retail web sales.

For more information about the outage, click here.

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