51K

51K (피프티원케이, FIFTYONE.K) is a South Korean talent management agency founded in 2009 by actor So Ji-sub and headquartered in Gangnam, Seoul. The agency name carries deliberate meaning: the number 51 reflects a humble mindset, acknowledging that 51 out of 100 is just enough to move forward, while K stands for Kingdom, representing a shared journey with artists and fans. What began as a one-man agency for So Ji-sub himself evolved into a boutique roster of established Korean actors and performers.

51K represents a selective, prestige-focused slate of talent. Core artists include So Ji-sub, the A-list actor behind Battleship Island, Oh My Venus, Doctor Lawyer (2022), and Netflix action-thriller Mercy for None (June 2025); Taecyeon of 2PM, who built a parallel acting career in dramas like Vincenzo; N (Cha Hak-yeon) of VIXX, who transitioned into acting and music under the agency; and actor Lee Seung-woo. In February 2026, actress Seo Ji-hye (born 1996, known for Crash Landing on You) signed exclusively with 51K.

The agency operates on a boutique model, prioritizing depth of management over roster size. This approach has positioned 51K as one of the more respected actor-focused agencies in Korean entertainment, distinct from the idol factory model that dominates the industry.