The following is a portion of Dennis Gartman’s famous list of trading rules.
RULE #1: Never, ever, under any circumstance, should one add to a losing position ... not EVER!
Averaging down into a losing trade is the only thing that will assuredly take you out of the investment business. This is what took Long Term Capital Management out. This is what took Barings Brothers out; this is what took Sumitomo Copper out, and this is what takes most losing traders and investors out.
RULE #2: Never, ever, under any circumstance, should one add to a losing position ... not EVER!
We trust our point is made. If "location, location, location" are the first three rules of investing in real estate, then the first two rules of trading equities, debt, commodities, currencies, and so on are these: never add to a losing position.
RULE #3: Learn to trade like a mercenary guerrilla
The great Jesse Livermore once said that it is not our duty to trade upon the bullish side, nor the bearish side, but upon the winning side. This is brilliance of the first order. We must indeed learn to fight/invest on the winning side, and we must be willing to change sides immediately when one side has gained the upper hand.
RULE #4: Don't hold on to losing positions
Capital is in two varieties: Mental and Real, and, of the two, the mental capital is the most important.
Holding on to losing positions costs real capital as one's account balance is depleted, but it can exhaust one's mental capital even more seriously as one holds to the losing trade, becoming more and more fearful with each passing minute, day and week, avoiding potentially profitable trades while one nurtures the losing position.
RULE #5: Go where the strength is
The objective of what we are after is not to buy low and to sell high, but to buy high and to sell higher, or to sell short low and to buy lower. We can never know what price is really "low," nor what price is really "high." We can, however, have a modest chance at knowing what the trend is and acting on that trend. We can buy higher and we can sell higher still if the trend is up. Conversely, we can sell short at low prices and we can cover at lower prices if the trend is still down. However, we've no idea how high high is, nor how low low is.
RULE #6: Sell markets that show the greatest weakness; buy markets that show the greatest strength.
Metaphorically, when bearish we need to throw our rocks into the wettest paper sack for it will break the most readily, while in bull markets we need to ride the strongest wind for it shall carry us farther than others.
RULE #7: In a Bull Market we can only be long or neutral; in a bear market we can only be bearish or neutral
In a bull market we can be neutral, modestly long, or aggressively long--getting into the last position after a protracted bull run into which we've added to our winning position all along the way. Conversely, in a bear market we can be neutral, modestly short, or aggressively short, but never, ever can we--or should we--be the opposite way even so slightly.
RULE #8: "Markets can remain illogical far longer than you or I can remain solvent."
The University of Chicago "boys" have argued for decades that the markets are rational, but we in the markets every day know otherwise. We must learn to accept that irrationality, deal with it, and move on.
RULE #9: Trading runs in cycles; some are good, some are bad, and there is nothing we can do about that other than accept it and act accordingly
Thus, when things are going well, trade often, trade large, and try to maximize the good fortune that is being bestowed upon you. However, when trading poorly, trade infrequently, trade very small, and continue to get steadily smaller until the winds have changed and the trading "gods" have chosen to smile upon you once again.
RULE #10: To trade/invest successfully, think like a fundamentalist; trade like a technician.
It is obviously imperative that we understand the economic fundamentals that will drive a market higher or lower, but we must understand the technicals as well. When we do, then and only then can we, or should we, trade.
RULE #11: Keep your technical systems simple
The greatest traders/investors we've had the honor to know over the years continue to employ the simplest trading schemes. They draw simple trend lines, they see and act on simple technical signals, they react swiftly, and they attribute it to their knowledge gained over the years that complexity is the home of the young and untested.
RULE #12: In trading/investing, an understanding of mass psychology is often more important than an understanding of economics
Markets are, as we like to say, the sum total of the wisdom and stupidity of all who trade in them, and they are collectively given over to the most basic components of the collective psychology. The dot-com bubble was indeed a bubble, but it grew from a small group to a larger group to the largest group, collectively fed by mass mania, until it ended. The economists among us missed the bull-run entirely, but that proves only that markets can indeed remain irrational, and that economic fundamentals may eventually hold the day but in the interim, psychology holds the moment.
And finally the most important rule of all:
RULE #13: Do more of that which is working and do less of that which is not
This is a simple rule in writing; this is a difficult rule to act upon. However, it synthesizes all the modest wisdom we've accumulated over thirty years of watching and trading in markets. Adding to a winning trade while cutting back on losing trades is the one true rule that holds--and it holds in life as well as in trading/investing.
This is what I have learned about the world of investing over three decades. I try each day to stand by my rules. I fail miserably at times, for I break them often, and when I do I lose money and mental capital, until such time as I return to my rules and try my very best to hold strongly to them.
The losses incurred are the inevitable tithe I must make to the markets to atone for my trading sins. I accept them, and I move on, but only after vowing that "I'll never do that again."