The main reason is that Tesla -- and only Tesla -- is switching business models from having investors put solar panels on house roofs and selling the power to t

The main reason is that Tesla -- and only Tesla -- is switching business models from having investors put solar panels on house roofs and selling the power to the homeowner, to the homeowner buying panels. This transition has been going on for the past 4 quarters. The article discusses it here: > SolarCity’s rapid growth was fueled in part by a no-money-down offering that enabled residential customers to pay a monthly fee to go solar. The business generated huge sales volumes but led to investor concern about debt. and it's easy to see, from the published financials, that this is a large effect.