These computer programs are great aids in reducing the number of stocks you might consider investment candidates down to a manageable number.
For example, you might run a screen looking for stocks that have grown by a certain percentage in sales revenue, earnings per share and dividend yield over the past five years.
Free ScreensMany sites on the Internet offer screening tools free and others for a fee. Some are quite sophisticated in the level of detail you can use in the screen.
Some sites tout the performance of their screens by tracking over time how well the stocks in a preset screen perform.
You might see a Web site claim their growth screen has beat the S&P 500 by 50% for the past four years or has grown by 125% in the past three years.
Some Web sites encourage you to subscribe to a “premium” service to gain access to their advance screening tools, which will give you stocks that have a tremendous record against the S&P 500.
Fine PrintRead the fine print before investing money in a screening service that promises or implies winning stocks every time.
One of the ways screens achieve results is through some very active trading. Here’s how some of them work.
Say a screen promises to pick the top growth stocks and it uses six different criteria to screen out all but the best and fastest growing stocks (so it says).
Assume that number is 50 individual stocks for the sake of discussion. To keep the screen’s cumulative gains high, the Web site assumes that an equal number of shares of all 50 stocks are bought.
Here’s the tricky part. At the end of the month, the screen is re-run and reconstituted, which means stocks from the original screen that have slipped in performance are dropped and hot, new stocks are added.
Repeat PerformanceAt the end of the next month, the same thing happens, so the screen always has the top stocks in its portfolio, even if it has to turn over many of them each month to make sure only the fastest growing stocks are in the portfolio.
Does the screen produce the results it claims? Yes, it does, unless you discounted for taxes and commissions.
Can you achieve those results? Few of us can buy 50 individual stocks at a time and turning over 25% - 60% each month, would be a lot of work and run up a big tax bill, because the stocks you would be selling still are most likely posting gains, they just aren’t growing fast enough for the screen.
If you can only afford to buy a few stocks out of the screen, which ones do you buy and how do you know they aren’t the ones, which will fall off next month?
Your best use of screens is to narrow down investment candidates to a small number of stocks, then you can do further research. Don’t rely just on the screen for your buying decision.
ConclusionStock screens are great tools and there are plenty out there for you to use, just don’t make the mistake that you can easily duplicate a screen’s track record.
Stories in this Series
Stock Screening Basics
You Should be Using Stock Screens
Characteristics of a Good Stock Screen
Don't Let Stock Screens Cloud Your Judgment
Stock Screens for All Investors
Stock Screening Tools You May Want to Consider
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