Shares in Metaplanet rallied 15.7% on Oct. 15 after the Japanese investment firm announced its latest purchase of around 107 Bitcoin, worth around $6.7 million.

Metaplanet’s latest purchase brings its total stash to 855.5 Bitcoin (BTC) — worth over $56.1 million — the firm said in an Oct. 15 statement.

The firm said it spent nearly $6.7 million (1 billion yen) to buy 106.976 BTC, paying around $62,520 per coin — 5.8% under Bitcoin’s market price of $66,200 at the time of Metaplanet’s announcement.

Details of Metaplanet’s latest Bitcoin purchase. Source: Metaplanet

Metaplanet (TYO: 3350) traded at 1,105 yen ($7.38) before the Tokyo Stock Exchange broke for lunch at 11:30 am local time on Oct. 15, up 15.7% from its Oct. 14 close, Google Finance data shows.

Metaplanet’s change in share price over the last five days. Source: Google Finance

Its share price is up 480% since it unveiled its Bitcoin investment strategy in early April.

Metaplanet has now paid the equivalent of $53.2 million for the 855 Bitcoin it owns and is up 5.4% on its Bitcoin investment.

The latest Bitcoin buy follows four earlier purchases this month that have more than doubled Metaplanet’s Bitcoin holdings.

The firm bought 109 BTC on Oct. 11 and 108.8 Bitcoin days earlier on Oct. 7.

Earlier this month, Metaplanet also purchased a combined 132 Bitcoin in two batches on Oct. 1 and Oct. 3, Bitcoin Treasuries data shows.

Related: Japanese Bitcoin investor Metaplanet works with Ripple’s partner SBI

Bitcoin rallied over 9% to $65,500 between Metaplanet’s Bitcoin purchase on Oct. 11 and its buy today, CoinGecko data shows.

Metaplanet CEO Simon Gerovich has admitted his company’s Bitcoin investment strategy was inspired by MicroStrategy and its executive chairman Michael Saylor — whose firm currently holds over 252,000 Bitcoin worth $16.45 billion.

Gerovich’s firm said in May that it would adopt an “entire range of capital market instruments” to bolster its Bitcoin reserves — similar to MicroStrategy’s playbook.

It included taking out a $6.8 million loan from one of its shareholders to buy more Bitcoin in August.

Metaplanet boasts the 23rd largest Bitcoin holdings among public companies, according to Bitcoin Treasuries.