A shipping experiment that started in India has made it to America’s West Coast and could spread across the U.S. sometime next year. That’s according to a new report by Bloomberg, which suggests that a new in-house Amazon delivery service will help it get more third-party goods to shoppers for free inside two days.

The trial, which is called Seller Flex, has Amazon taking over control of shipping decisions from some third-party sellers, says Bloomberg. In some cases Amazon may deliver the goods, in others it would use firms like UPS and FedEx that currently ship many of the e-tailer’s wares. The move is meant to give Amazon a way to leverage its logistics chops to get goods to people more efficiently. That could allow it to assert its dominance in retail even further.

It’s not the first time rumors have swirled about Amazon taking more of its package logistics on for itself. Last year, there was speculation that the e-tailer sought to build a more flexible kind of shipping service that could enable it to, for instance, provide after-hours deliveries.

To find out more about how companies work out the best way to make deliveries, read our recent article on the increasingly complex algorithms that get packages to your door.