The stock price of Japan's most expensive securities company is flying high largely in part due to its cryptocurrency business segment.

According to a report by Bloomberg on Wednesday, Monex Group Inc. is currently the most expensive stock on the TOPIX index. The Japanese index is based on all domestic common stocks listed on the Tokyo Stock Exchange (TYO).

Monex, which owns the Japanese cryptocurrency exchange Coincheck, acquired the marketplace for $33.5 million in April 2018 and has since experienced phenomenal growth from investors looking to capitalize on bitcoin's latest bull run.

The brokerage's venture into cryptocurrency earned the company 2.42 billion yen (US$22.9 million) pretax profit in the quarter ended Dec. 31, 2020, increasing its quarter-on-quarter growth threefold, company filings show.

“People are starting to re-evaluate us,” said the company's CEO, Oki Matsumoto, saying investors are moving beyond the idea Monex is more than just stockbroking, as cited in the report.

Despite bitcoin's 10% dip on Tuesday and Monex's own share price falling 3.9% on Wednesday, the online securities trading company is still well ahead with yearly gains exceeding 131%, TYO data shows.

See also: Japan’s SBI in Talks Over Joint Venture to Make Crypto a Core Revenue: Source

"The soaring price of bitcoin has spurred trading activity and encouraged more individual investors to jump into the fray," said SMBC Nikko analyst Takayuki Hara in a Feb. 22 note to investors. "There has been sharp growth in earnings at Coincheck."