Bitcoin mining companies MARA (formerly Marathon Digital) and Hut 8 announced substantial Bitcoin purchases on Thursday as more and more firms look to stockpile the leading cryptocurrency within their treasuries.

MARA expanded upon a previously announced Bitcoin purchase from last week, boosting the tally to 15,574 Bitcoin at a total price of about $1.53 billion. Last week, the first disclosed the first tranche of the purchase, buying 11,774 BTC for $1.1 billion. Thursday's announcement points to the firm adding another 3,800 BTC at a price around $400 million.

The added tally boosts MARA's treasury reserve to 44,394 BTC—over $4.4 billion worth. Meanwhile, Hut 8 said that it added 990 Bitcoin at a price of about $100 million, giving it 10,096 BTC (over $1 billion) in its reserve.

The MARA purchase comes off the back of two separate convertible note offerings in which it raised nearly $2 billion across November and December. The company, which trades on the Nasdaq under the MARA ticker, has now nearly tripled its Bitcoin holdings in the last calendar year, according to its most recent SEC filings.

While Marathon’s average price of purchase was around $98,529 per Bitcoin, Hut 8 acquired its 990 Bitcoin for an average cost of $101,710—both marks above the current Bitcoin price of $97,951. 

“We believe deeply in our operating business and that building a strategic Bitcoin reserve will fortify our financial position as we pursue large-scale growth initiatives across power and digital infrastructure,” said Hut 8 CEO Asher Genoot, in a statement.

The two Bitcoin miners both rank inside the top six of Bitcoin holdings among publicly traded companies, according to data from Bitcoin Treasuries. MARA is down over 5% on the day, however, while Hut 8 has dipped by nearly 7%, mirroring a crypto market plunge that took hold in the early afternoon.

Bitcoin mining is the process of adding and verifying blocks on the Bitcoin blockchain, a process that requires intensive energy and hardware resources. Typically, miners today are large companies with warehouses full of expensive, cutting-edge computers, as individual miners are rarely able to win blocks—though it happens occasionally.

Edited by Andrew Hayward