Kia Motors' shares closed 9.7 percent higher in Seoul on Wednesday, reaching 97,700 won per share after a South Korean newspaper reported it would close a deal with Apple as soon as Feb 17.
That's the highest level for the stock since August 1998, according to data provided by Refinitiv Eikon.
According to the newspaper Dong-a Ilbo, Apple is seeking to invest 4 trillion won in Kia for a partnership to roll out Apple cars by 2024.
Kia would initially produce 100,000 cars per year for Apple at its factory in the US state of Georgia, with the capacity increasing to 400,000 annually. The reportedly could be signed as early as February 17.
Last month, Hyundai, the owner of Kia, was reported to be in discussions with Apple to develop electric cars, propelling Hyundai shares to their best in at least two decades.
Hyundai has been open to joining forces with other companies, including tech firms. It is working with Chinese search giant Baidu and US chipmaker Nvidia on autonomous driving.
Hyundai 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 as potential options.