Important Don'ts for Investors, from Philip Fisher

In investing, the actions you don't take are as important as the actions you do take. Here is some of Philip Fisher's advice on what you should not do.

1. Don't overstress diversification

Investment advisors and the financial media constantly expound the virtues of diversification with the help of a catchy cliche: "Don't put all your eggs in one basket." However, as Fisher noted, once you start putting your eggs in a multitude of baskets, not all of them end up in attractive places, and it becomes difficult to keep track of all your eggs.

Fisher, who owned at most only 30 stocks at any point in his career, had a better solution. Spend time thoroughly researching and understanding a company, and if it clearly meets the 15 points he set forth, you should make a meaningful investment. Fisher would agree with Mark Twain when he said, "Put all your eggs in one basket, and watch that basket!"

2. Don't follow the crowd

Following the crowds into investment fads, such as the "Nifty Fifty" in the early 1970s or tech stocks in the late 1990s, can be dangerous to your financial health. On the flip side, searching in areas the crowd has left behind can be extremely profitable. Sir Isaac Newton once lamented that he could calculate the motion of heavenly bodies, but not the madness of crowds. Fisher would heartily agree.

3. Don't quibble over eighths and quarters

After extensive research, you've found a company that you think will prosper in the decades ahead, and the stock is currently selling at a reasonable price. Should you delay or forgo your investment to wait for a price a few pennies below the current price?

Fisher told the story of a skilled investor who wanted to purchase shares in a particular company whose stock closed that day at $35.50 per share. However, the investor refused to pay more than $35. The stock never again sold at $35 and over the next 25 years, increased in value to more than $500 per share. The investor missed out on a tremendous gain in a vain attempt to save 50 cents per share.

Even Warren Buffett is prone to this type of mental error. Buffett began purchasing Wal-Mart many years ago, but stopped buying when the price moved up a little. Buffett admits that this mistake cost Berkshire Hathaway shareholders about $10 billion. Even the Oracle of Omaha could have benefited from Fisher's advice not to quibble over eighths and quarters.