South Korean automaker Hyundai and its affiliate Kia on Monday denied news reports they were in talks with Apple for a joint project to make autonomous vehicles, sending their shares tumbling.

Shares in South Korean automaker Hyundai soared Friday on the back of reports it was in talks with Apple for a joint project to manufacture self-driving electric vehicles.

The California technology colossus behind the iPhone has confirmed its interest in self-driving cars, but experts are trying to deduce the secretive company's plans for traction in a market where others have been speeding along.