Bitcoin's meteoric rise has weighed on South Korea's small-cap stocks. It has surged nearly 35 percent since Mr. Trump won the election on Nov. 5, while the small-cap Costco index has lost 8 percent, making it likely to be Asia's worst performer this year. Analysts said the decline was partly due to small investors selling stocks for bitcoin, adding to the rout that has wiped about a fifth of the index's value this year. Trading volume on South Korean cryptocurrency exchanges has now exceeded that of the benchmark KOSPI index. Hong Songuk, a digital asset analyst at NH Investment & Securities, said that since bitcoin spot ETFs were banned in South Korea, investors have bet on leveraged funds that trade bitcoin futures, while others have bought shares in MicroStrategy (MSTR. O).