It's an game with virtual values. If you were to handle such a highly endowed company professionally there would never be so much money left over. Somehow the bigger version of Las Vegas without so many neon lights.
But to answer your question from my sight: In 1929 days before the big crash came there where fluctuations up to 20% in the days before. I'm not sure how long the stock game will work, but since the last crash 2008 the stock exchange was supportet by a lot of tax money and a lot of artificial trading, it's no longer in touch with reality.
Just my sight and i'm sure you'll find someone here who's more an expert.