Every investor should know the bullish and bearish arguments about the stocks they're interested in. In this video, Fool.com analysts Jason Moser and Austin Smith discuss the bearish perspective on Clean Energy Fuels  (NASDAQ: CLNE). The company provides solutions for the trucking industry to operate on natural gas, and has built a nationwide infrastructure of natural gas fueling stations along essential truck corridors. But there are a few red flags to be aware of. Will natural gas continue to be adopted? The business depends on widespread implementation of natural gas as an alternative fuel – if another source becomes more popular, Clean Energy could have considerable setbacks. Right now natural gas is cheap – and that benefits Clean Energy Fuels – but what happens to Clean Energy Fuels if natural gas prices go up? It would no doubt decrease demand for Clean Energy's services. Currently, T. Boone Pickens is a major holder of Clean Energy Fuels stock. If, at some point, he decides to liquidate his position, the market would be flooded with CLNE shares and push the price down.

Austin Smith has no positions in the stocks mentioned above. Jason Moser has no positions in the stocks mentioned above. The Motley Fool owns shares of Clean Energy Fuels. Motley Fool newsletter services recommend Clean Energy Fuels. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.