MicroStrategy Inc bought about 51,780 Bitcoin for around US$4.6 billion, the largest purchase by the crypto hedge-fund proxy since it began acquiring the digital asset more than four years ago.

The enterprise software maker, whose corporate strategy includes buying the cryptocurrency, bought the tokens between Nov 11 and Nov 17, according to a US Securities and Exchange Commission filing on Nov 18. It now holds more than US$29 billion in Bitcoin.

MicroStrategy co-founder and Chairman Michael Saylor decided to invest in Bitcoin in 2020 as a hedge against inflation. The firm initially used cash to make the purchases and has shifted to using the proceeds from the issuance and sale of stock, as well as convertible debt sales to leverage its buying power.

Saylor has doubled down on the strategy this year, saying the company aims to raise US$42 billion over the next three years.