What happened 

Shares of solar manufacturing giant First Solar, Inc. (NASDAQ:FSLR) jumped 19.5% in October, according to data provided by S&P Global Market Intelligence, after reporting earnings that were far better than expected. 

So what 

Revenue of $1.09 billion and net income of $209.7 million both beat expectations and management also increased full-year earnings guidance to $2.05-$2.30 per share. High panel and solar project prices in the quarter were a huge tailwind for the company. 

Utility scale solar installation with a power line in the background.

Image source: First Solar.

What really shocked investors was that First Solar booked 4.5 GW of panel and system sales in the quarter, more than it makes in a year. A boost in demand is coming from the fact that First Solar won't be affected by potential solar import tariffs and project developers are booking tariff-free panels to lock up supply in 2018 and beyond. 

Now what 

First Solar has now booked most of its production for the next two years, which gives it a tremendous amount of certainty. If tariffs come back at a level that's favorable to First Solar we could also see a capacity expansion to exploit its preferred position in the U.S. market. This is still one of the best, and safest, solar stocks on the market and last month's earnings report shows why. 

Travis Hoium owns shares of First Solar. The Motley Fool recommends First Solar. The Motley Fool has a disclosure policy.