Bitcoin investment firms raise large sums of money, often through a mix of equity and debt, to buy and hold bitcoin. Their stock becomes another way for investors to bet on the price of bitcoin.
Michael Saylor, founder of Strategy (formerly MicroStrategy), popularized the model, converting its cash reserves into bitcoin beginning in 2020. The move transformed the software company into a de facto bitcoin holding company, with the value of its stock soaring as bitcoin rallied. It's now one of the world's largest owners of bitcoin.