Diversifying your portfolio is always important when trading in the stock market, but first of all, what’s my portfolio? Your portfolio is a collection of all the stocks you own. To diversify your portfolio is to buy shares in many different companies and industries. This allows some “safety” if the price of one of your stocks dives. Generally the overall price of a stock goes up from year to year, so diversifying your portfolio will ensure that you make money all the time.