Almost everyone is happy when markets trend higher. But unfortunately, this is almost never the case. Each week at Stockpickr, we look for short-term catalysts and snapback plays that could move higher no matter what the market does, and I present these picks each Monday morning in Rocket Stocks portfolio. With more than 8,000 publicly traded companies, there are bound to be a handful of stocks that move higher whether the market is up huge or down huge. These picks are for the short term, meaning that investors who buy these stocks, based on these catalysts, should hold them for no longer than one or two days (or until the catalyst has triggered). However, selling stocks and locking in gains is one of the toughest things for investors to do; that is why I started writing this weekly update on Wednesday mornings. I would sell First Solar ( FSLR), which rose 6% as oil continued its climb higher. Alternative-energy stocks seem to get their groove at the moment oil touches $80. The business models make it conducive for such companies to be profitable. I would also get out of FreightCar America ( RAIL), which is also up 6%. Nothing changed here fundamentally; we just caught it perfectly. The freight car company still has a ton of cash on the balance sheets, a high short position and an interesting business model. It's definitely one to keep on the watch list.