I don't know how the selling actually works... I've tried to sell a few stocks this morning but it didn't go throuhg and just my luck the market dived!!! jw
The share price is based on the real share price, so your sell orders will only go through if there's been some activity on the share. If there's no trading at all on the share your buy/sell orders won't be processed.
Well its more to do with the lesser known/traded shares where volume becomes a big issue and you might not be able to sell your shares unless there are trades.