Jeonbuk Hyundai Motors midfielder Kang Sang-yoon has been rated as the most expensive player in the top Korean football league. The CIES Football Observatory, a research group within the Switzerland-based International Centre for Sports Studies (CIES), released a list of transfer values for players in 60 leagues around the world Thursday. Kang, the 21-year-old midfielder who helped Jeonbuk to the K League 1 title and the Korea Cup victory, was valued at up to 3.5 million euros ($4.09 million). A key cog in Jeonbuk's midfield, Kang earned a place in the season-end K League 1 Best XI squad for the first time in 2025, his fourth professional season. Kang appeared in 34 matches and recorded four assists. Gus Poyet, who coached Jeonbuk last season, often praised Kang's speed and energy level, and predicted Kang will play in Europe someday. Pohang Steelers striker Lee Ho-jae was next in the transfer value with an estimated maximum of 3.3 million euros, followed by Gangwon FC center back Shin Min-ha with 3 million euros. FC Barcelona sensation Lamine Yamal topped the list with 343 million euros.