It’s official—Walmart has agreed to buy the fast-growing e-commerce startup Jet.com for $3B in cash and $300M of the retailer's shares.

“We believe the acquisition of Jet accelerates our progress,” Walmart CEO Doug McMillon (pictured) said in the company’s announcement today. “Walmart.com will grow faster, the seamless shopping experience we’re pursuing will happen quicker and we’ll enable the Jet brand to be even more successful.”

The two companies will still function as separate entities. Jet will maintain its distinct brand and founder and CEO Marc Lore will stay aboard as the head of Walmart’s online division, Bloomberg reports. The two will combine proprietary technology and customer data, including access to Jet’s growing customer base—which accounts for more than 400,000 new visitors a month.

Jet is barely a year old, but already the company has amassed $500M in capital from venture capitalist firm New Enterprise Associates and bank Goldman Sachs. 

The Walmart takeover further illustrates how difficult it can be for the new kid on the block to navigate the challenges of e-commerce. Jet had hoped to take on Amazon by offering cheaper prices—but that goal would require billions in funding and strong relationships with suppliers, the Wall Street Journal reports.