Quote from Cutten:
Your title says how to cut losses, your post says how to handle swings, which is it?
The way to handle swings is to reduce your size small enough that normal market fluctuations do not lose you enough money to bother you, or to use options to limit your maximum loss to an acceptable amount.
As for cutting losses, which I understand as exiting once you realise you are wrong, you need to first define what would prove your position to be incorrect. If that thing then occurs, you're probably wrong and should exit. Make sure you trade small enough, or are sufficiently hedged with options, that the amount of loss in this event is acceptable to you.
In my opinion, it is pretty hard to make more than 2 or 3 times your risk on an annual basis trading global macro style, and most good traders don't get much above 1:1. So if you are gunning for 30% then you should be prepared for 20-30% drawdowns too on occasion.
To get an idea of the volatility vs returns, just look at any major macro move. For example, the move in oil from $30 to $147 and back. Both on the way up and the way down, there were significant pullbacks - many of 10%, some of 20%, and the rally had a pullback from 77 to 49 (36% pullback). So you had a 390% gain, with maximum 36% pullback, a very nice 11:1 ratio. In reality though you would never buy the low and sell the high. More likely, even the best traders got long maybe somewhere in the 40s and sold either in the 90s or maybe 120something. Or the true believers were long from 30 and got stopped out on the way back down at 90 or 80 or 70. So the real ratios were probably more like 150% or 200% profit with a 36% drawdown, a 5.5:1 ratio. Still very nice, most trades aren't that good.
Here are some other examples from the last year or so:
Short pound, from 2.00 to 1.40 = 30% return, max pullback was 11%. slightly under 3:1 ratio.
Short S&P, from 1500 down to 700 =53% profit, maximum drawdown was 27%. Roughly 2:1 ratio.
Short oil from 147 to 40. 73% profit, max DD was about 25-30%. 2.5:1 ratio.
So as you can see, even excellent macro trades generally have profit only 2-3 times the maximum pullback. Some rare trades are better than that, but most will be in the 2-3 range. So IF you can select these good trades and avoid bad ones, you could get 2-3 times your risk on a portfolio basis. If you select multiple trades, your DD will be lower due to diversification. In the real world, you won't ride every, or even most, macro trade opportunities to the full. You will miss some, you will be on the wrong side of some, you will exit prematurely or enter later on others etc. So although theoretically a perfect macro portfolio could make 5-10 times its risk, in the real world it's more like 1 times as a reasonable goal, and 2 or 3 times would be superstar performance.
George Soros for example has averaged 30-40% over various long periods, and he has had occasional peak-valley drawdowns of similar amounts (although his calendar year results are better in terms of risk, it's peak/valley that matters).
IMO, macro trading is all about risking 1, 2, 3% per trade and making 3, 6, 9% when you are right on the trade, doing that 3-10 times per year, and aiming for 15%-50%, whilst keeping drawdowns to 10% or less ideally, and definitely below 20%. If you have a good run, compounding equity allows you to turn a good 4-5 month run into potentially a 50%+ year. It is tempting to trade bigger and try to score 20-30% on a single trade, but except a few rare options trading opportunities (e.g. calling a market crash in advance), that is very hard to do without taking commensurately large risk. Remember our 2.5:1 ratio. If you are trying to score 25% on a trade, your risk is likely to be 10%. A 10% drawdown is something you should strive to avoid in any given year. Losing that on one single trade is insane. So keep your size down.