Matthew Kim, popularly known as BM which stands for Big Matthew, is the main dancer and lead rapper of the group KARD under DSP Media.
BM first participated in the show Kpop Star and became a trainee for 4 years and a half. He debuted as a member of KARD on July 19, 2017 with the mini album Hola Hola. He represents the letter K and the King card. BM eventually debuted as a soloist with his first digital single, "Broken Me" on June 9, 2021.
In 2021, BM began selling "Big Tiddie Gang" merchandise through his apparel brand Staydium, with a share of the proceeds going to breast cancer research and awareness.