(CNN) — Shares of Hyundai and Kia plunged on Monday after the South Korean automakers said they were not in talks with Apple to develop self-driving cars after all.

“We are not having talks with Apple about developing self-driving cars,” Hyundai said in a statement.

The statement added that Hyundai has received requests from “numerous companies” about developing self-driving electric cars, but that “no decision has been made as we are in the beginning stage.”

Kia Motors, which is part of the Hyundai Motor Group, referred CNN Business to its parent company’s statement.

Apple declined to comment.

The announcement jolted investors who had been betting on some kind of tie-up between the companies based on weeks of speculation and local news reports. Kia’s stock plummeted nearly 15%, its worst day since at least 2001, according to data provider Eikon Refinitiv. The fall wiped $5.4 billion off its market value.

Hyundai’s stock fell 6.2%, losing about $2.8 billion in market value.

News media in the country reported just last week that Kia was closing in on a major deal with Apple for a partnership to build a new vehicle, sending Kia’s stock to its best day in more than two decades.

And last month, Hyundai was reported to be in discussions with the iPhone maker to develop electric cars. The news at the time propelled Hyundai’s shares, also to their best day in at least two decades.

Interest from Apple in South Korea’s automakers made sense. Analysts have pointed out that Hyundai has been open to joining forces with other companies and even tech firms; it already has partnerships with with Chinese search giant Baidu and US chipmaker Nvidia on autonomous driving, for example.

The automaker has also already made significant strides on next-generation vehicles, including hydrogen fuel-cell cars and an electric vehicle manufacturing platform it unveiled in December.

But Apple may also choose to enter multiple partnerships, with analysts floating other major carmakers such as Honda, Tata Motors’ Jaguar Land Rover and Geely, the Chinese owner of Volvo, as potential options.

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