The new service, called Amazon Supply Chain Services (ASCS), lets companies pay Amazon to handle the behind-the-scenes work of getting products from factories to customers’ doors. That includes shipping goods across oceans, storing them in warehouses and delivering packages to homes seven days a week.

Big names like Procter & Gamble, 3M, Lands’ End and American Eagle are already signed up.

Amazon compared the move to the launch of Amazon Web Services, its cloud computing business.

AWS started as an internal tool Amazon built for itself, then became a massive business by selling that same technology to other companies. Amazon is betting it can do the same thing with shipping and logistics.

Since 2006, independent sellers on Amazon’s marketplace have used a program called Fulfillment by Amazon to let the company handle packing and shipping their orders. Amazon said those sellers have shipped more than 80 billion items through the programme.

But until now, most of Amazon’s logistics muscle was only available to businesses that sold products on Amazon’s own site.

The move puts Amazon in more direct competition with shipping giants like FedEx, UPS and DHL.

On Wall Street, investors punished UPS, which was down 10%, and FedEx, which fell nine percent

Amazon was up around one percent.