Good question. The answer to is what is known as market capitalization which we have broken down here on the StockTradingToGo site previously,
http://www.stocktradingtogo.com/2007...apitalization/
"Market capitalization, or market cap, is simply the measurement of a company’s total value or worth. If a company wants to buy out another company, they are going to be paying the market cap for it."
So if company XYZ issues 10,000 shares at $100 a piece, the company has a worth of $1,000,000. This is the price another company would pay to buy the company at today's value. The reason a stock will never trade for pennies when it is worth $1 is because the market deems the market value to be at that level.
And even though the company already received the original $1 million, if the market cap is only $1,000 then someone could in theory come in and buy up the whole company for $1,000 and take it over completely. As soon as any one person acquires 50.1% they are the majority owner.
Hope this helps a bit!