A Hyundai Motor logo can be seen on a glass door in a corporate branch in Seoul on July 23, 2015

Jung Yeon-Je | AFP | Getty Images

South Korean automakers Hyundai Motor and Kia Motors said Monday they were not in talks with Apple to develop an autonomous vehicle.

Hyundai Motor stock fell 6.41% on Monday morning in South Korea, while Kia Motors stock fell 13.2%. Other subsidiaries such as Hyundai Wia, Hyundai Mobis and Hyundai Glovis also fell sharply.

“Hyundai Motor is receiving requests from several companies to collaborate on the joint development of autonomous electric vehicles, but nothing has been decided as it is in the early stages,” the company said, according to a CNBC translation of a regulatory filing.

“Hyundai Motor is not in talks with Apple about autonomous vehicle development,” he added.

Subsidiary Kia Motors, the second largest automobile manufacturer in South Korea after Hyundai, submitted a similar report. The company is currently evaluating the prospect of working with “multiple companies overseas” on autonomous electric vehicles, but nothing has been decided yet.

Kia Motors also said it was not in talks with Apple.

Hyundai initially said it was in early talks with Apple last month, but later revised the statement and made no mention of the iPhone maker. This led to a surge in the shares of Hyundai and its affiliates, including Kia Motors, at the time.

This month, CNBC reported that Apple is on the verge of signing a deal with Hyundai-Kia to manufacture an Apple-branded autonomous electric vehicle at the Kia assembly plant in West Point, Georgia. Sources told CNBC’s Phil LeBeau that an agreement has not yet been reached and that Apple may ultimately decide to work separately or in addition to Hyundai with another automaker.

Stocks can keep falling

According to Sung Yop Chung, private investors have had Hyundai Motor and Kia shares valued at approximately 915.7 billion won (817 million US dollars) and 798.8 billion, respectively, since January 8th speculation about a possible collaboration with Apple Won (around $ 713 million). Regional Head of Automobiles and Components at Daiwa Capital Markets.

“After the negative sentiment from both (Hyundai Motor) and Kia’s filing this morning highlighting that there is currently no EV collaboration with Apple, worst case scenario suggests Kia’s shares could correct up to 31%” he told CNBC’s Chery Kang.

Speculation about Apple’s entry into the auto business has been rife for several years, but nothing specific has occurred.

Some Wall Street analysts see the automotive industry as a new market for Apple to grow into, but others caution against the reality of making an Apple-branded car as it could potentially mean high investments for low margins.

– CNBC’s Chery Kang contributed to this report.