The unveiling was originally planned for August 8, but Tesla has pushed the event back to October to give the teams more time, Bloomberg News reported, citing people familiar with the decision.
Tesla shares were down 6.4 percent in afternoon trading.
Earlier Thursday, Tesla shares had risen for 11 straight days in moves thanks in part to the Robotaxis event, which Musk has described as a platform for the company’s ambitious autonomous driving technology.
The outspoken Musk has a history of making bold predictions about the prospects for autonomous vehicles, saying that traditional autos will one day be as obsolete as horses and buggies and flip phones will replace them.
But Musk has fallen short of estimates on the self-driving technology’s timeline, after previously predicting the company would achieve breakthroughs by 2018.
Wedbush analyst Dan Ives said Thursday’s “nervous” market reaction to the delay was negative, but the later timeframe “could make the actual Robotaxis event and prototype better and more eye-catching.”
Tesla won’t be the first entrant into the autonomous taxi sector, with companies like Waymo already operating vehicles in some US cities.
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