SAN FRANCISCO (Reuters) - Rivian is opening up sales of its delivery vans to fleets of all sizes in the United States, the electric vehicle maker said on Monday, more than a year after ending its exclusive deal with shareholder Amazon.

Rivian, known for its flagship R1S SUVs and R1T pickup trucks, has seen demand beyond Amazon for its commercial vans and has been testing them with large fleets.

Van sales, along with its plans to roll out its smaller, less expensive R2 SUVs in 2026, will be crucial to Rivian's success as broader demand for EVs has eased amid high borrowing costs.

"Rivian has been trialing its commercial van with several large fleets in the U.S., and preparing its fleet management process for the mass market," the company said in a statement. "These pilots have paved the way to enable Rivian to open sales further."

Rivian ended its exclusive deal for van sales with Amazon in late 2023 but reaffirmed its commitment to fulfilling an order for 100,000 vans by 2030. Amazon currently has 20,000 Rivian vans in its fleet.

After the exclusive ended, U.S. wireless carrier AT&T was the first company to purchase some vans from Rivian in a pilot program. It did not disclose the number of vehicles it bought or the financial terms.

Rivian's announcement on Monday comes months after it resolved a component shortage that hamstrung production of its vans as well as SUVs and pickups.

Last month, the company surpassed analysts' expectations for fourth-quarter deliveries. It has been cutting costs by renegotiating supplier contracts and revamping its manufacturing processes to turn a gross profit for the fourth quarter.

Rivian is set to report fourth-quarter results on February 20.