First Solar (FSLR) stock sank after Goldman Sachs downgraded the company’s stock from buy to sell on Monday.

Goldman Sachs also set a target price for First Solar stock at $45.  Analyst Brian Lee claimed that the company wasn’t prepared to handle shifts in the industry and that some of the company’s peers were in a better position than it, reports MarketWatch.

Lee also went on to say that First Solar stock doesn’t get enough public exposure in the rooftop solar panel market. He predicts that the rooftop solar panel market will see a 45% expansion in the United States by 2014, The Street notes.

FSLR stock was down 9% as of Monday afternoon.