Tesla Motors Inc. (TSLA) has offered to buy SolarCity Corp. (SCTY) in a $ billion deal. Now that Tesla is in all probability buying SolarCity. We know the deal is going to go through anyway. The question is the Your SCTY shares become TSLA shares at a fixed ratio. So if SCTY drops. Tesla Motors said it would buy solar panel installer SolarCity for $ billion in shares to form a one-stop clean energy shop. The deal is a major.