A Japan-run language school that saw its stock soar almost 12-fold last year is planning to expand into new business areas as its chief executive officer tries to keep the rally alive.

RareJob Inc., a Tokyo-based online English conversation school, or eikaiwa, that uses teachers in the Philippines, will focus on areas including leadership training and job placement, said Gaku Nakamura, the company's founder and chief executive officer, in an interview. Nakamura said one of his goals was to boost the company's market value to ¥100 billion ($922 million) from its current level of about ¥25 billion.

RareJob surged 1,093 percent in 2019, the second-best performance in Japan's Mothers market of smaller shares, after it surprised investors by saying earnings would jump. Analysts — and history — suggest it will be difficult to keep up those gains after the company's valuation exceeded estimated profit 100 times over.