The Financial Post reports in its Friday edition that Uber plans to invest as much as $1.25-billion in carmaker Rivian to help launch a robotaxi fleet that will be available in the United States, Canada and Europe over the next five years (all figures U.S.). A Bloomberg dispatch to the Post says Uber or its fleet partners will buy 10,000 autonomous Rivian R2 robotaxis and make them available exclusively on the Uber app starting in San Francisco and Miami in 2028, the two companies said in a statement Thursday. As part of the partnership, Uber has committed to an initial $300-million investment in Rivian, subject to regulatory approval. The financing may increase to as much as $1.25-billion through 2031 if certain undisclosed "autonomous milestones" are met, the companies said. They also have the option to negotiate the purchase of as many as 40,000 more Rivian robotaxis beginning in 2030. Shares of Rivian jumped as much as 9.4 per cent in New York, while rival Tesla fell as much as 3.3 per cent. The deal represents one of Uber's biggest robotaxi partnerships to date as its ride-hailing businesses faces competition from a wave of robotaxi operators. Uber has struck agreements with over 20 self-driving car developers.