How big is Apple? Their individual share price is above $500. Well, it used to be. Now it’s gone below $500 a share. What could have caused this? A tiny Chinese company that is giving Apple a big headache.

We reported earlier this week that Proview, a Chinese display manufacturer, holds the trademark to the iPad name. The Shenzhen Intermediate People’s Court rejected Apple’s claim to the iPad name and now the company is appealing to the Higher People’s Court.

The implications of this are huge as Proview is asking for a ban on iPad exports and imports. While sales of the iPad are already being hurt in China with reports of government officials seizing iPad shipments, the export ban would hurt the most. Since all the world’s iPads are made in China, none of the product could leave the country.

All of this is hurting Apple’s shares as it has dropped individual share price to below $500. Apple’s share price is now at $492 at the time of writing.

If Proview has its way, expect Apple’s shares to take an even bigger hit. The iPad is one of Apple’s biggest sellers and with the iPad 3 rumored to launch in March, any delay could hurt their bottom line.