Obviously, companies of this size aren't going to disappear overnight. Investors should not assume, however, that the shares of IBM, GM and Union Carbide are safe just because they belong to big companies. Size is not nearly as important to an equity investor as knowing where the company's earnings are heading. It is virtually impossible to forecast the earnings of IBM, General Motors and Union Cabide with any degree of accuracy. Therefore, their stock's have below average safety ratings.
Beta reflects the statistical movement of a stock price compared to the market.
If a stock's price moves up and down exactly in sync with the market, it will have a Beta of 1.00. High Beta stocks are more volatile than the market, and less predictable. Therefore, they are riskier than the market. Ironically, they are not necessarily riskier than some low Beta stocks. Certain stocks, such as gold stocks, are very volatile, but tend to move counter to the market.