SunPower (SPWR) - One of the fastest growing solar companies, with one of the most efficient cells around.
Sharp Electronics - The largest photovoltaic cell manufacturer in the world.
Suntech Power Holdings - A Chinese photovoltaic cell company that is muscling its way into world solar markets.
JA Solar Holdings, - A Chinese PV company that only sells monocrystalline solar cells; it lets its customers take care of building the modules and systems.
Solarfun Power Holdings - Another Chinese PV company that operates 90% in Europe and makes most of its money by selling modules, rather than individual cells.
Evergreen Solar - A solar company that produces string ribbon PV cells and operates at all production levels from silicon wafer to power system.
Kyocera - A Japanese electronics company that is also a major manufacturer of solar cells.
Q-Cells - A privately owned, German solar manufacturer.
BP, Mitsubishi, and Sanyo - Not primarily photovoltaic cell manufacturers, but heavy market competitors nonetheless.
EMCORE - A Concentrated Photovoltaic System manufacturer that uses Gallium arsenide PV cells and got its start in the solar business making power cells for satellites.
Energy Conversion Devices - This company uses amorphous thin-film silicon in its ultra-thin, albeit low-efficiency solar cells.