Tesla, Rivian, and Uber Are Down Between 16% and 26%. Here's the Best Buy for the Robotaxi Takeover.

Tesla (NASDAQ: TSLA) is down about 16% in 2026 as is Uber (NYSE: UBER). Rivian (NASDAQ: RIVN) is down roughly 26%. Sometimes it's been worse for each them this year. These are three very different companies, one shared storyline: robotaxis are coming, and Wall Street can't yet decide which wins. I think the answer is hiding in plain sight, in a way most investors slept on.

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Tesla is betting it can do everything itself

Tesla's robotaxis already drive without a safety monitor in Austin, Texas, Dallas, Houston, and Miami. No person behind the wheel. No person in the passenger seat watching, either. That's a real risk and a big nod of progress. Elon Musk said in January that it would go nationwide by year-end, per CNBC. Maybe. Musk's timelines have a habit of slipping.

Here's the thing about Tesla's approach: it's all in and it controls the whole stack. Tesla builds the car. Tesla writes the software. Tesla runs the fleet. If it works, Tesla keeps every dollar. If it doesn't scale as fast as promised, Tesla eats the cost alone. That's a high-conviction, high-risk bet, and the stock's valuation already assumes a lot of it goes right.

Uber isn't picking a winner. It's betting on all of them

Uber doesn't build cars. It doesn't write self-driving software, either. What Uber builds is demand, millions of riders opening an app expecting a car to show up. That turns out to matter a lot, because somebody still has to fill empty robotaxi seats, and right now that somebody is Uber.

Look at who Uber's working with. Waymo rides already book through the Uber app in several cities. WeRide just got Spain's first national permit for autonomous passenger vehicles, with Uber attached. Wayve launched robotaxi rides with Uber in London. And in March, Uber agreed to invest as much as $1.25 billion in Rivian, with an option to buy as many as 50,000 autonomous Rivian robotaxis by 2030.

Uber doesn't need Tesla to win. It doesn't need any single company to win. It just needs people to keep opening the app, which will almost definitely happen. With Uber's underlying ride-hailing business still growing, this is a solid bet.

Rivian just became a robotaxi supplier, whether investors noticed or not

Rivian's piece of this story is the one that surprised me most. Uber isn't just buying Rivian vehicles. It's funding them, committing up to $1.25 billion through 2031, tied to Rivian hitting autonomy milestones. The plan: 10,000 fully autonomous R2-based robotaxis to start, deployed in San Francisco and Miami in 2028, expanding to 25 cities by 2031.

That's a real opportunity. It's also a long way off. Rivian still has to build those cars profitably, hit the autonomy targets Uber is tying its money to, and keep its core electric vehicle (EV) business from burning too much cash in the meantime. Recent recalls and a departing chief financial officer haven't helped sentiment. Rivian is really just a supplier here, not a company setting any terms.

The best buy is Uber

Given a choice between all three, I'd buy Uber. Here's why: Uber wins no matter which hardware or software stack ultimately dominates robotaxis. Tesla needs its own technology to work, on its own timeline, with no backup plan. Rivian needs its autonomy software to hit milestones years from now, on someone else's money. Uber just needs robotaxis, generally, to become a bigger part of how people get around, and then needs people to keep booking through its app.

In other words, Uber's whole business has always been selling other people's cars, other people's time, other people's labor, and taking a cut. Robots replacing the driver doesn't break that model; it just strips out the highest cost and the biggest headache, fewer human drivers to recruit and retain, which should only make Uber's cut more profitable over time.

Micah Zimmerman has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Tesla. The Motley Fool recommends Uber Technologies. The Motley Fool has a disclosure policy.