Rivian Automotive's (RIVN 0.82%) strategy for success was never solely about retail electric vehicle (EV) sales. Early in its development, the company announced a deal with e-commerce giant Amazon to deliver 100,000 commercial electric delivery vans by the end of the decade. More than 30,000 are now in service, and Rivian is now growing its fleet business through a new agreement with Uber Technologies (UBER +8.53%). But there's a twist with the Uber business, and it could have big ramifications for Rivian and its stock. Focus on technology Rivian and Uber announced a new partnership last month that is expected to bring more than $1 billion of new capital to Rivian and a fleet of electric vehicles to Uber. Rather than commercial vans like Amazon, this fleet business will use Rivian's new R2 SUV, which just began customer production. Uber ordered 10,000 new R2 SUVs for delivery in 2028 and plans to purchase 40,000 more in 2030. These will be fully autonomous R2 EVs, though, and that's what makes this deal a game changer for both Rivian and Uber. The deal with Uber highlights Rivian's push into self-driving technology. Late last year, Rivian held its first "Autonomy and AI Day," during which it revealed an in-house autonomy processor. Uber's investment could bring up to $1.25 billion in capital to Rivian over the next five years, but it's the underlying technology that investors will be paying most attention to. Uber will help highlight that as it did today. In its earnings release today, Uber CFO Balaji Krishnamurthy stated, From this position of strength, we're investing with conviction in the significant opportunities ahead, while taking a capital-efficient approach to AVs [autonomous vehicles] and embracing AI to drive growth and productivity. The investment in Rivian and its AI technology will be at the