NEW YORK ( TheStreet) -- Shorts betting against First Solar ( FSLR) increased interest by more than 8% in the two-week period that included the solar company's most recent -- and bleak -- outlook. The move up in First Solar short interest was the largest increase among investors making bearish bets on alternative energy stocks. The question isn't what's already been done by the shorts, though, but whether it continues as the patten and whether the pattern is specific to First Solar or is a stand-in for the entire solar sector. The sudden spike in First Solar short bets could be the sign of more to come or could have been motivated by the typical volatile First Solar earnings trade, and as such is a short opportunity already gone. In the two weeks between Feb. 15 and Feb. 29 -- First Solar reported its earnings on Feb. 27 -- short interest in the solar energy company increased by 8.3%. First Solar short interest reached 31.2% as a percentage of float, and 21.5% as a percentage of shares outstanding as of Feb. 29. In its earnings, First Solar reported warranty charges related to solar panel performance issues in intense heat conditions. Some First Solar experts see in this revelation another great profit opportunity in a stock that could now head down to single-digit territory. However, there's also the belief after last year's monumental collapse in First Solar shares that the short opportunity is more or less over, and there is a risk in keeping a short on the stock given the prospect for a larger company to acquire First Solar at a premium . If the latter is the case, then this short interest spike in First Solar should settle down when the Nasdaq next reports short interest for the first two weeks of March. First Solar shares tanked after its earnings report on Feb. 27 and shorts could have been playing the stock simply as an earnings trade. First Solar shares are always volatile on earnings and often move down by double-digits the day after earnings if the company's outlook is negative. First Solar provided an outlook on global demand that was cautious, and while it maintained its earnings guidance, stated production cutbacks and a revision to revenue and cash flow guidance has led some analysts to assume it ultimately won't make its earnings guidance either.