$50B wiped from Tesla after BTC buy â but MasterCard and Twitter surge Teslaâs stock fell 7% following its announcement that it invested $1.5 billion of its cash reserves in the cryptocurrency. 40112 Total views News Electric car manufacturer Tesla has seen more than $55 billion wiped from its market cap since announcing the purchase of $1.5 billion in Bitcoin four days ago â but Twitter and MasterCard have headed in the other direction. Since Teslaâs announcement on Monday, the electric car giantâs stock price has dropped 7% from $869.52 ($834.6 billion market cap). It is currently trading at $811.66 ($779 billion market cap). While there may be other factors behind the share price drop, some investors, such as Baker Avenue Wealth Management chief strategist King Lip, are concerned that holding 8% of the company's cash reserve in a volatile asset is an unnecessary risk, stating: