A stock is defined as a share of ownership of a publicly-traded company that is traded on a stock exchange. Common stocks are securities, sold to the public, that constitute an ownership stake in a corporation. They come in all sizes -- you can invest in a large, like Jollibee or  PLDT , or a smaller, micro-cap company that shows potential for profit

When you buy a share of a stock, you automatically own a percentage of the firm, and an ownership stake of its assets. If you paid PHP 100 for a share of stock, and the stock appreciates in value by, say, 10% during the period you own it, you've earned PHP 10 on your stock investment.

That's the idea behind buying stocks -- to invest in solid, well-managed companies that turn a profit. A company that succeeds on those fronts stands a good chance of its stock price growing in value, while the company, in going public, makes use of the proceeds of the original stock sale to reach growth goals and manage operating expenses. The company can use the cash to invest in new markets, research new products, hire more workers and better advertise their products and services, among other things.

In most cases, it doesn't take much effort to buy stock shares and own a piece of a company. You would simply pay what the market is demanding (market price) for a particular stock, via a stockbroker either over the phone or via a digital device, and you're good to go. You'll receive confirmation of your purchase and can sell the stock whenever you like, hopefully for a profit.