A market index tracks the performance of a group of stocks, which either represents the market as a whole or a specific sector of the market, like technology or retail companies. You’re likely to hear most about the S&P 500, the Nasdaq composite and the Dow Jones Industrial Average; they are often used as proxies for the performance of the overall market.

Diversification allows you to recover from the loss of your total investment (20% of your portfolio) by gains of 10% in the two best companies (25% x 40%) and 4% in the remaining two companies (10% x 40%). Even though your overall portfolio value dropped by 6% (20% loss minus 14% gain), it is considerably better than having been invested solely in company E.

What are your financial goals for 10, 15, or 20 or more years down the line, and how do you plan on getting there? What is your level of risk tolerance, and what sort of investment approach will you take (value investing, dividend investing, or some combination of multiple strategies)? As you consciously outline your financial goals and the type of investor you want to be, you can experience success as a disciplined investor in the long run and stay on track with your plans.
While some people do buy winning tickets or a common stock that quadruples or more in a year, it is extremely unlikely, since relying upon luck is an investment strategy that only the foolish or most desperate would choose to follow. In our quest for success, we often overlook the most powerful tools available to us: time and the magic of compounding interest. Investing regularly, avoiding unnecessary financial risk, and letting your money work for you over a period of years and decades is a certain way to amass significant assets.
Buy “the basket”: Can’t decide which of the companies in a particular industry will be the long-term winner? Buy ’em all! Buying a basket of stocks takes the pressure off picking “the one.” Having a stake in all the players that pass muster in your analysis means you won’t miss out if one takes off, and you can use gains from that winner to offset any losses. This strategy will also help you identify which company is “the one” so you can double down on your position if desired.