Amazon shares jumped nearly 5 percent after reports the e-retailer could open a book-rental service costing around $79 annually.

The Seattle-based company didn't comment on the report, published by the Wall Street Journal.

Already the world's No. 1 bookseller, Amazon now might offer a rental library of older titles that could be rented via its Amazon Prime option that already offers on-demand TV and films, along with two-day shipping.

The service would be an obvious challenge to Netflix, whose shares fell slightly Monday, as well as to other on-demand services, such as Hulu, which is currently being auctioned by its owners that include News Corp. and NBCUniversal. Netflix shares fell slightly in early Monday trading.

Amazon isn't a publisher itself, so major publishers including Viacom's Simon & Schuster line, News' Harper Collins and other might also be interested in dealing with Amazon, as well as others offering an online rental service.

In April, Amazon started offering links to 11,000 U.S. public libraries using its Kindle Lending Library feature. Its technology partner is OverDrive, the Cleveland-based e-publisher which already has 300,000 titles from leading publishers.

Google, which has digitized older books in university libraries might also get into the field.

Besides selling books and other electronics, Amazon has already sold millions of Kindles for reading new titles. The company is expected to announce a Kindle tablet device sometime in the fourth quarter.

Electronic book rentals would put a 21st century shine on a classic American tradition. The lending library was a part of 19th and 20th century U.S. tradition when it was promoted by major retailers and even drugstore chains.