Shares of SPI Energy Co. Ltd. /zigman2/quotes/207301620/composite SPI -7.32% soared 54% in premarket trading, but that paled in comparison to the 1,236.5% rocket ride on massive volume in the previous session. The stock had run up as much as 4,154% intraday on Wednesday, before paring gains, after the company, which offers photovoltaic solutions for business, residential, government and utility customers, said it was starting an electric-vehicle subsidiary, as MarketWatch's Mark DeCambre reported. The stock's trading volume about an hour ahead of Thursday's open was 2.5 million shares; on Wednesday, volume was 348.3 million shares. Meanwhile, shares of Sunworks Inc. /zigman2/quotes/208800639/composite SUNW -6.31% , which also makes photovoltaic-based power systems, shot up 353% on volume of 17.5 million shares in Thursday's premarket, after climbing 50.4% on volume of 110.5 million shares on Wednesday. The stocks' rallies premarket comes while futures /zigman2/quotes/209948968/delayed ES00 -0.73% for the S&P 500 /zigman2/quotes/210599714/realtime SPX -1.21% are slipping 0.3%.