Puts have been quite popular on Clean Energy Fuels Corp. (CLNE - 18.40) lately, with near-term put open interest edging up 5% since April 23. The stock's Schaeffer's put/call open interest ratio (SOIR) of 0.98 is now ranked in the 98th percentile of its annual range. In other words, short-term speculators have rarely been more put-heavy toward the equity.

Options players' appetite for CLNE puts is echoed by data from the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX). As it turns out, the stock's 50-day put/call volume ratio of 0.29 ranks higher than 98% of other such annual readings, suggesting that bearish bets have been scooped up over bullish at a near annual-high clip in recent months.

The black cloud hanging over CLNE has drifted outside of the options arena, as well, where short sellers increased their bearish presence by 15.3% in the most recent reporting period. Short interest now accounts for a staggering 23.7% of the stock's available float.

Not to be left off of this bearish bandwagon, no less than 89% of analysts maintain a "hold" or "sell" suggestion toward CLNE. Plus, the average 12-month price-target of $20.67 represents a middling 12% premium to the equity's current perch.

At an initial glance of CLNE's technical backdrop, this pessimistic skew may seem a bit puzzling. CLNE has tacked on an impressive 46% in 2012. Also, during the course of the past 60 trading sessions, the stock has outperformed the broader S&P 500 Index (SPX) by nearly 12 percentage points, on a relative-strength basis. However, after tagging an all-time high of $24.75 on March 21, CLNE pulled back sharply, but was able to find support from its rising 80-day moving average.

CLNE's recent downturn may account for some of the Street's bearish bias. Another viable explanation for the gloom and doom directed toward CLNE could be the natural gas issue's upcoming first-quarter earnings report, scheduled for release on Monday, May 7. CLNE has fallen short of analysts' bottom-line expectations in two of the last four quarters.

At last check, the stock was up around 1% in early trading to hover near $18.40.