The service will be offered at $9.99 per month, in line with major rivals, and it will offer a competitive catalog of songs, the sources said. Amazon is finalizing licenses with labels for the service, which likely will be launched in late summer or early fall, the sources said.

Amazon, which offers a free streaming music service with a limited catalog to subscribers of its Prime shipping and video service, did not respond to a request for comment about the new, full-fledged music plan.

Although it will be a late entrant to the crowded streaming space, Amazon believes a comprehensive music service is important to its bid to be a one-stop shop for content and goods, the sources said.

The new music offering also is intended to increase the appeal of the Amazon Echo, its home speaker, which searches the Internet and orders products from the retailer with voice commands.

"A music service will further increase the daily interactions between Amazon and its customer base," said former music executive Jay Samit when told about the company's plan.