Technically though, although he owns the company, Tesla, still he reports to the board of Directors. So it's not just Elon Musk who decided when or how they are going to invest or accept bitcoin. Perhaps there is a middle between the company and bitcoin, meaning there is a broker, so it's not a "direct buy". It could be the top exchanges like Binance or Kraken or even Coinbase. For Dogecoin, we have news that he owns big as well? or he is just trolling us with his Dogecoin tweet?