The architect of the company’s audacious Bitcoin-hoarding strategy explains why he calls the crypto “a flow of money from the 20th century to the 21st century.”

Shares in MicroStrategy, the largest corporate holder of bitcoin, initially jumped and then fell Monday after the software company said it had bought $5.4 billion of the cryptocurrency.

MicroStrategy is unique on the stock market because it essentially acts like a leveraged Bitcoin ETF. Chief Executive Officer Michael Saylor, one of the biggest evangelists for the digital coin, began buying it for his company in 2020, and it held 252,220 bitcoins as of the end of the third quarter.