I am a Certified Professional in Supply Management (CPSM) who made his first investment by buying 4 shares of Home Depot in 1996. I am a fairly concentrated investor by most people's standards. I currently own a total of 11 stocks with 7 of those making up over 90% of the value of the total portfolio. My favorite investing quote is the following by Benjamin Graham from Security Analysis: "Analysis connotes the careful study of available facts with the attempt to draw conclusions there from based on established principles and sound logic. It is part of the scientific method. But in applying analysis to the field of securities we encounter the serious obstacle that investment is by nature not an exact science. The same is true; however of law and medicine, for here also both individual skill (art) and chance are important factors in determining success or failure. Nevertheless, in these professions analysis is not only useful but indispensable; so that the same should probably be true in the field of investment and possible that of speculation"