Samah Aluminum shares jumped sharply today, closing near KRW 65,800, up 11.90% from the previous day. The broader KOSPI was flat during the session, but this stock's outsize gain signals a catalyst specific to the company or its sector. The market was quiet. Yet this one stock surged nearly 12%, not a market-wide move. That points to a stock- or sector-specific story. What kind of company is this? Samah Aluminum originally manufactured aluminum foil for cigarette packaging and tuna cans—a classic, long-established company. But in 1998, it became the first in South Korea to develop secondary-battery-grade aluminum foil. Today, the company supplies positive-electrode current-collector foil to South Korea's three major battery makers: LG Energy Solution, Samsung SDI, and SK On . It has transformed completely. SK On is understood to source 90% of its aluminum foil from Samah. Today's jump: aluminum raw-material prices are the real driver LME aluminum pric...