I'm guessing Amazon and Apple are not worried about this development; in other Walmart news, Jet.com’s president is leaving just 18 months after the $3 billion Walmart acquisition (Recode)
"Walmart customers will be able to read the books through Rakuten Kobo e-reading devices — which have not taken hold with Americans the way Amazon’s Kindle and Barnes & Noble’s Nook have.
The partnership is part of Walmart’s effort to ensure that its online offerings include every conceivable product line, giving shoppers no reason to click over to Amazon. But by many measures, Walmart is arriving late to the digital book party.
Amazon, which built its business around book sales in its early days, has a huge head start. Beyond that, the e-book market has shown signs of fizzling, as screen-weary readers turn back to print copies."Walmart Makes a Late Entry Into the E-Book Market - The New York Times