What: Shares of First Solar (NASDAQ:FSLR) rose 10% in the month of August, made even more impressive when you consider that solar stocks in general dropped during the month.

The Guggenheim Solar ETF dropped 14% in the month, and losses were widespread as oil prices dropped.  

So what: First Solar's stock jumped early in the month after the company reported first-quarter earnings. The gains tapered off later in the month, but that coincided with a drop in solar stocks generally.

The two things investors should know about the quarter was management's guidance for $3.30 to $3.60 per share in earnings for the full year and a 1.4% increase in panel conversion efficiency from a year ago to 15.4%. A more efficient panel will make the company more competitive when bidding on solar projects long term and will potentially lead to even higher margins.

FSLR Chart

FSLR data by YCharts.

Now what: First Solar is one of the best companies in the solar industry, and its increasing profits while competitors are losing money is a testament to its position. With efficiency expected to increase toward 20% in coming years, its position as an industry leader should continue. And even after a strong April, shares trading at 13 times the high end of this year's earnings is a good deal for investors.