Tokyo-listed firm Metaplanet (MTPLF) has added an additional 136 bitcoin (BTC) to its treasury, after earlier this month taking its holdings to over 20,000 coins.

The acquisition was made at an average purchase price just under $112,000 per bitcoin and lifts the total the firm spent on BTC to more than $2 billion.

Metaplanet tracks the performance of its investment through a BTC yield metric, which measures the growth of bitcoin held per fully diluted share rather than traditional yield earned on assets held.

From April through June, Metaplanet posted a BTC yield of 129.4%. For the third quarter to date, the figure stands at 30.8%

The company’s 20,136 BTC stash makes it the sixth-largest publicly traded bitcoin treasury company. Collectively, these companies hold over 1 million BTC, with the lion’s share coming from Strategy’s 638,460 bitcoin treasury.

Shares are down more than 30% over the past month, hit by a modest decline in the price of bitcoin along with a shrinking mNAV — the premium of the company market cap versus its bitcoin holdings.