One of the basic laws of physics states that a body in motion will continue in motion in the direction it is going until interrupted by another force.
That basic physics law also applies to stocks and mutual funds. To see this trend it will be very apparent in a weekly or monthly chart rather than a daily chart. The daily chart shows too much noise (random movement).
In the Friday edition of Investor's Business Daily you will find 37 weekly charts on the back page of Section 2. One of the common occurrences among these issues is the steady upward progression of price, many with an angle of 30 degrees or more. The up movement of price may have been going on for many months. This is the kind of stock you want to own and even add to your position as it continues upward.
Most brokers talk about dollar cost averaging and mean adding to a stock as it goes down. That is stupid. There is only one right way to dollar cost average and that is when it is going up - NEVER down. Averaging down will put you in the poor house.
Today's stock market (end of 1999) we see the upward momentum of almost all the major stock averages - the DOW Jones Industrials, the S&P500, the Russell 2000 and many more. Some of these indexes are headed for the stratosphere. No, I have no idea how high or how far is up, but remain 100% invested to take advantage of this runaway bull. The market will tell me when to sell.
For anyone holding individual stocks about the only thing you can do is set a trailing stop-loss order so that when the issue turns you will be out with a nice profit. Don't try to predict the top because you will sell too soon. Let the stock itself tell you when to get out. The amount of the stop will be up to you, but I like about 10% of Friday's closing price. Never move the stop down.
There are people who buy mutual funds and put them away and never look to see how they are doing. This is a mistake. You are hurting your financial future if you do not regularly review your funds. Monthly is best, never less that quarterly. Momentum applies here too and even more so because many funds have a bias to a particular sector of the market. There are big caps, small caps, regional, international, value, etc., etc., etc. A policy to enhance your income is to see which sectors or groups are doing best and be invested in a fund that is heavily in that sector.
Mutual funds of a certain sector will run up for months at a time, even years, but when that sector becomes weak you should sell immediately and buy a stronger one. If you are with a discount broker there will be no commission to switch and, of course, you only buy no-load funds. Never blindly buy and hold any fund.
As you become aware of the momentum of various sectors and switch to stay with the strongest you can easily double your current return.