Bitcoin buying is back. Corporate crypto heavyweight Strategy announced Monday that it bought over $21 million worth of Bitcoin last week, bringing its total holdings to roughly $70 billion. The company, led by the flamboyant billionaire Michael Saylor, funded the purchase by selling more than 125,000 shares of its common stock and using $500,000 in cash. It also spent roughly $192 million to repurchase nearly 2 million shares of STRC, a type of preferred stock that makes regular payments to investors.