Yingli Green Energy

Last week was another volatile one for investors. Among the 10 biggest losers were a handful of solar energy stocks that got hammered for a second week in a row, a Dutch data security firm undergoing a dustup, and a few companies that are experiencing the pressures of Wall Street scrutiny for the first time since going public.

LDK Solar has long depended on demand driven by government subsidies from countries such as Germany, Spain and Italy, which makes it vulnerable in this period of European austerity. Trefis has revised its estimates for LDK Solar down -- but still meaningfully above the market price.

Yes, we've seen this movie before: As costly oil makes solar look good, investors pile in -- only to be let down when overcapacity sets in and oil prices tumble again. But this time, solar's rebound may be on somewhat firmer ground. Investors, though, still need to be cautious.

Oregon is the latest state to notch a big win in the effort to attract green jobs: Silicon Valley solar company Solexant has announced plans to build a large factory to produce thin-film solar panels near Portland. Oregon gets jobs; Solexant gets a $25 million loan and $18.75 million in tax credits.

A fake oil tycoon. The biggest sports event in the world. A Formula One racing team. What do they have in common? They're all part of branding initiatives by solar panel makers seeking to make their names in a fast-growing industry.