Kia has filed trademark applications for several new K-series vehicle names in the United States, potentially expanding the naming strategy already used for the K4 and K5. The latest filings cover K2, K3, K6, K7 and K8, while the K9 name is notably absent.
Kia Expands Its K-Series Trademark Portfolio
Trademark applications filed with the US Patent & Trademark Office cover five additional single-digit K names: K2, K3, K6, K7 and K8. The filings follow Kia’s shift in recent years from traditional vehicle names to numbered designations for at least two US-market models.
The K4 is currently on sale and succeeded the Forte. The Forte compact sedan was known as the K3 in Korea, but when the model was replaced, Kia introduced the K4 name worldwide.
The K5 is Kia’s midsize sedan and was formerly known as the Optima. The model had been called the K5 in much of the world for two generations before Kia adopted the name in the US.
Where Could Kia Use the New K Names?
The K3 designation is already used for Kia’s overseas replacement for the discontinued Rio compact car. The Rio has been absent from the US market for years, but the K3 name remains available if the model returns.
Kia’s other numbered vehicles include the K8, which replaced the full-size Cadenza but is not sold in the US, and the K9 luxury sedan, which was sold in the US as the K900 until 2021.
Kia has not given a K-number designation to any of its SUVs anywhere in the world. That makes a sudden change from Sportage to K6 unlikely based solely on the existing naming pattern. At the same time, Kia’s current lineup does not suggest that it would need enough additional sedan names to use every newly filed trademark.
Why Kia May Be Refiling the Trademarks
Another possibility is that Kia is seeking to prevent other companies from using the marks. US trademark law generally requires a trademark to be used in commerce, but that requirement does not begin immediately. The first declaration of use is required “between the fifth and sixth years after the registration date.”
Trademark records indicate that Kia may be applying to register the marks again rather than claiming that it is currently using them. The K6 mark, for example, was first registered in September 2020, and the six-year reminder was sent out in September 2025. Now that six years have passed, Kia has filed a new application.
Why the K-Series Names Matter
Trademark protection is an important part of maintaining a brand identity and preventing others from using names that could create confusion. The source points to Porsche as an example: The automaker wanted to call its car the 901, but Peugeot owned three-digit numbers with a 0 in the middle, resulting in the 911.
For Kia, maintaining control of the K-series names provides a relatively inexpensive way to prevent other companies from adopting similar marks. The source gives the hypothetical example of a company such as Chery selling a “Chery Comaro” sports car in the US.
Why Kia Did Not Refile K9
The missing K9 trademark is significant because Kia previously held the mark but chose to use K900 for the US market instead. The old K9 trademark has since expired, and Kia did not file a new application for it.
For now, Kia’s latest filings cover K2, K3, K6, K7 and K8, adding several more possible names to the automaker’s K-series trademark portfolio while leaving K9 off the list.
