NEW YORK - Walmart is buying fast-growing online retailer Jet.com for $3 billion in cash plus $300 million in stock, scooping up a newcomer that launched a year ago with the intention of challenging online leader Amazon.

The hefty price underscores how Walmart is trying to compete more aggressively and effectively for younger and more affluent customers as it has seen its online business growth slow, even with big investments in distribution centers and expanding services.As part of the deal, Jet.com co-founder and CEO Marc Lore will oversee both that site and walmart.com, and will report to Walmart Stores Inc. Chief Executive Doug McMillon. Lore brings to the role a rich e-commerce background as founder of Quidsi, the parent of Diapers.com, which was bought by Amazon for $500 million in 2010.Analysts say the acquisition still won't enable Walmart to catch up to Amazon in sales, but it will help narrow that gap and should widen the distance between Walmart and other online retailers.The deal also reflects the difficulties for startups like Jet.com of making it on their own in a sphere Amazon dominates with its network of distribution hubs and the powerful asset of its Prime membership program.The move follows a series of acquisitions by major traditional retailers of online startups, with Hudson's Bay, which owns Saks Fifth Avenue, purchasing flash-sales site Gilt Group and Bed Bath & Beyond buying One Kings Lane.While not a startup, Walmart itself announced in June that it announced it was forming a partnership with JD.com in China to bolster its presence in that market.As part of the deal, which Walmart expects to close this year upon regulatory approval, Walmart and Jet.com will maintain separate brands - for now.Walmart.com will stay focused on the company's low price strategy and Jet.com will still provide a curated assortment of products.The acquisition will help Walmart grab a higher-income customer who typically is younger than its own shoppers.Jet.com, launched in July 2015, sells 12 million products, from jeans to diapers and has been growing fast. It has more than 400,000 new shoppers added monthly and an average of 25,000 daily processed orders.Walmart says it will incorporate some of Jet.com's "smart" technology that lowers prices in real time by looking for ways to cut costs.It is built on a pricing algorithm that determines which sellers are the most efficient in value and shipping and adjusts prices based on what items are in the checkout cart, as well as how far the desired products are from the shopper's home. So shoppers are encouraged to add more to build a more efficient cart and buy items labeled "smart cart" for more savings.McMillon said Walmart customers likely will see lower prices and new brands aimed at millennials that have been carried by Jet.com.Walmart customers may also have more control over creating their own basket to save money."We have some cool ideas on how the two brands can work together over time," he said. As for perhaps merging the two sites eventually, McMillon said Walmart wants to be thoughtful about how it approaches that.Lore cited the benefits of Walmart's purchasing scale, sourcing capabilities, distribution footprint and digital assets together with Jet.com's team and technology. Jet.com, which touts its service, delivers to two-thirds of the country overnight in its purple boxes. In some high-density regions such as New York City, Jet often can offer same-day delivery at no additional cost.Lore told The Associated Press that he can see helping Walmart with speeding up shipping, among other things.In its fiscal year ended in January, Walmart had online sales of $13.7 billion, a fraction of its total revenue of $482.1 billion.And its online figure pales in comparison to Amazon.com's annual net revenue of $107 billion.Apple.com is the only brick-and-mortar retailer that outranks Walmart in online sales in the U.S.But Walmart reported in May that global e-commerce sales rose 7 percent in the first quarter, weaker than the 8 percent in the previous quarter and far below the 20 percent increases seen less than two years ago.So it trimmed its free-shipping pilot program ShippingPass to two-day delivery from three and cut a dollar off the membership to $49 a year in an attempt to answer Amazon's Prime program.But while Amazon's Prime membership costs $99 a year, it comes with a lot of perks like streaming music and video and household subscriptions.