Michael Saylor's Microstrategy (MSTR) announces the purchase of another 271 bitcoins (BTC-USD) for $15M, or an average price of $55,387 each. That brings the company's holdings to 91,850 bitcoins purchased at an average of $24.4K each.The price of $55.4K each suggests Microstrategy made the purchase prior to Elon Musk's market-cratering tweet last night.Bitcoin is off its panicky low of $45K, and now trading just above $50K. MSTR is down 7.7% premarket.Michael Saylor last night took to Twitter to question Elon Musk's reasoning on Bitcoin mining energy usage.