went out three times in 2013. The cause of Amazon’s most recent outage is unclear, but it’s costly. Inc. isn’t saying what caused its site to be briefly unavailable to some users Thursday, but it wasn’t the first time the e-commerce giant experienced an outage.

Amazon, No. 1 in the Internet Retailer 2015 Top 500 Guide, went down for about 46 minutes in August 2013. It was the third time that year the online retailer experienced an outage. In May 2013, was inaccessible for about 10 minutes while in January of the same year it went down for 49 minutes. Each time, Amazon did not specify what caused the outage. An Amazon representative did not return an email request for comment on Thursday’s outage, and the company has not addressed the issue on its Facebook or Twitter pages.

On Friday, website performance management firm Catchpoint Systems Inc. wrote in a blog post that Amazon makes $1,084 per second, which means Thursday’s 20-minute outage cost it $1.3 million based on those figures. “What caused the outage is still unclear, but it’s safe to assume the company felt the blow,” Catchpoint writes.

Internet Retailer estimates that the 20-minute outage cost Amazon about $3.75 million.

Amazon wasn’t the only retailer to suffer downtime Thursday. Catchpoint data shows that Macy’s Inc., No. 7 in the  Top 500, suffered a series of outages between 3:30 a.m. and  4:45 a.m. Eastern.


“It’s possible that this was a result of server maintenance considering the time of day the failures occurred, which may have saved Macy’s from having to deal with any costly consequences,” Catchpoint writes.

As with Amazon, Macy’s didn’t address the outage on social media, and a Macy’s spokesman did not return a request for comment.

Meanwhile, other retailers have experienced site performance issues recently, owing more to heavy traffic than anything else. Target Corp., No. 18 in the Top 500, went down on the morning of Cyber Monday (the Monday after Thanksgiving) due to a spike in traffic, while luxury retailer Neiman Marcus (No. 43) and online electronics retailer Newegg (No. 17) both went down on Black Friday, the Friday after Thanksgiving.

It’s not always heavy traffic that causes issues, however. Online marketplace eBay Inc. became unavailable for about three hours on the Wednesday before Thanksgiving last year, an outage the company attributed to “a public Internet domain change that had an unanticipated impact on processing inside the eBay platform.” Hackers took down Newegg’s site in late September, attempting to extort the company in exchange for bitcoin. Chief operating officer James Wu said the retailer didn’t pay, and wound up stepping up its security measures as a direct result of the attack.