Tesla stock posted modest gains after Elon Musk's EV maker finally launched its robotaxi service in Austin, Texas to a small group of users on Sunday.

Tesla has started giving rides in driverless Model Y SUVs in Austin. Details are still sparse, but limited service is open to vetted and invited riders.

The vehicles will have safety monitors and may not operate in bad weather, making them more restricted than the fully autonomous vehicles promised by Elon Musk.