US tech business intelligence firm Microstrategy today announced that it has raised $650 million to buy Bitcoin.

In a note to investors today, MicroStrategy said that it closed the sale of $650 million in debt securities. The sale was valued at $400 million on Monday.

MicroStrategy said that it "intends to invest the net proceeds from the sale of the notes," about $634.9 million after deducting discounts, commissions and expenses, "in bitcoin."

MicroStrategy's CEO, Michael Saylor, is a big believer in Bitcoin. He bought $500 million of the currency in the second half of this year. He has tweeted incessantly about the coin since his purchase.

Saylor is one of several high-profile institutional investors to have invested in Bitcoin this year. They brought a flood of new money into crypto and renewed interest in Bitcoin. At the turn of the month, Bitcoin hit a new all-time high.

MicroStrategy must pay investors back at a rate of 0.75% per year, starting in June 2021 and ending in June 2025, unless MicroStrategy buys back the debt. Investors can cash the notes out for stock or cash.