Japanese listed company Metaplanet has doubled its Bitcoin holdings this month, buying more than 450 Bitcoins in four purchases. Today, Metaplanet announced the purchase of about 107 Bitcoins, worth about $6.7 million, and the company's stock price rose 15.7% today. The recent increase brings Metaplanet's total BTC holdings to 855.5. Since announcing its Bitcoin investment strategy in early April, Metaplanet's stock price has risen 480%. Metaplanet CEO Simon Gerovich said the company's Bitcoin investment strategy was inspired by MicroStrategy and its executive chairman Michael Saylor, whose company currently holds more than 252,000 Bitcoins, worth $16.45 billion. According to Bitcoin Treasuries, Metaplanet's Bitcoin holdings rank 23rd among listed companies. (Cointelegraph)