Short interest among solar and alternative energy stocks plunged during the two-week reporting period that ended on October 15. In the solar sector, four of the five companies we watch saw short interest fall, and the sole increase was a mere fraction of a point. All four alt energy stocks saw a decrease in short interest during the period.

First Solar Inc. (NASDAQ: FSLR) saw short interest increase by just 0.2% to 5.9 million shares, which represents 8% of the company’s float. Days to cover rose from three to four. In the two-week short interest period through October 15, shares rose nearly 28%. The stock’s 52-week range is $39.18 to $65.50 and it closed at $50.57 on Monday up about 0.3% for the day.

SunEdison Inc. (NYSE: SUNE) showed a decrease of 2.1% in short interest, to 91.46 million shares. About 29.3% of the company’s float is now short and days to cover remained unchanged at three. In the latest two-week short interest reporting period, the share price rose by 39.5%. The stock closed at $7.79 Monday night, up about 0.3% for the day, in a 52-week range of $6.56 to $33.45.

SunPower Corp. (NASDAQ: SPWR) short interest fell by 0.6% to 6.08 million shares, or 10.7% of the company’s float. In the two-week short interest period to October 15, the share price jumped by nearly 30%. The stock’s 52-week range is $18.25 to $35.11 and it closed at $24.73 on Monday, down about 1% for the day. Days to cover remained unchanged at five.

SolarCity Corp. (NASDAQ: SCTY) saw a short interest slip by 3.8% to 26.06 million shares, 43.5% of the company’s total float. Days to cover slid from 14 to 13. In the two-week short interest period, the share price rose by more than 13%. The stock’s 52-week range is $34.65 to $63.79, and shares closed at $38.84 Monday night, down about 1% for the day.

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Canadian Solar Inc. (NASDAQ: CSIQ) saw a decline of 6% in short interest in the two-week period to October 15. Some 15.2% of the total float, 6.44 million shares, were short, and days to cover remained unchanged at three. The company’s shares soared more than 36% over the two-week period. Shares closed Monday at $21.66, up about 4.7% for the day, in a 52-week range of $14.16 to $40.08.

FuelCell Energy Inc. (NASDAQ: FCEL) had a drop of 11.1% in short interest during the two-week period. About 14.8% of the company’s float, 37.77 million shares, was short and days to cover fell from 19 to 18. In the two-week short interest period, the shares jumped nearly 35%. The stock closed at $0.83 on Monday, down about 0.8% for the day, in a 52-week range of $0.64 to $2.30.

Plug Power Inc. (NASDAQ: PLUG) saw short interest decrease by 0.9% to 34.95 million shares. Days to cover rose from eight to 13 and about 20.3% of the company’s shares were short. In the two weeks to October 15, the stock’s share price rose by nearly 36%. The stock’s 52-week range is $1.56 to $5.48 and shares closed Monday at $2.41, up 4.3% for the day.

Clean Energy Fuels Corp. (NASDAQ: CLNE) saw a drop of 8.2% in short interest to 18.22 million shares. About 25.6% of the company’s float was short and days to cover remained unchanged at 13. Shares rose by about 8.5% in the two-week period. The stock closed at $5.35, up more than 1%, on Monday in a 52-week range of $3.73 to $10.48.

Pacific Ethanol Inc. (NASDAQ: PEIX) saw short interest drop by 11.5% in the two-week period to 2.91 million shares, about 7.2% of the company’s float. Days to cover slipped from five to four. The stock price rose nearly 6% in the two weeks to October 15. The stock closed at $5.68 on Monday, down about 7% on the day, in a 52-week range of $5.62 to $15.57.

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