Julia,
Julia said:
What I always find difficult is appreciating the end of an uptrend.
That can indeed be a difficult thing to appreciate.
I think it depends on your definition of a trend over the time frame you're considering. A long term investor's small correction might well be a short term trader's end of trend.
IMO, you first need to decide what you consider a trend for the stock you've purchased and your strategy. You then need to decide what you would consider the end of that trend. Numerous ways could then be used to indicate it.
For example, you might use a trend line with a certain amount of movement to the right or below the line signalling the end, or you might use a moving average with a cross below the MA signalling the end, or you might use two moving averages with a crossover signalling the end. A trailing stop is another possibility. With MAs and trailing stops though, you still need to decide what parameters to use with them, and it's likely that different parameters would best suit different stocks due to the differences in volatility (especially for short term systems). You might also decide to look for multiple conditions, for example: a cross below a trend line or MA and then either another few closes below the line or a certain percentage drop below the line, whichever came first.
And for a longer-term system, you might decide to base it on a weekly or even monthly chart rather than daily.
Whatever you choose though, there will always be cases where you get out too early, and the stock will turn back up minutes later and surge to new highs without you
. However, it's ultimately the overall profitability that counts, and getting out of a few too early is likely better than staying in many more for too long. If one does take off again, you can always buy back in (which of course leads to the opposite question of how to appreciate when a trend's starting or is continuing
).
would you say the use of a trailing stop loss is a reasonable device for exit
A trailing stop can be an excellent device for exit, but it may not suit a particular stock or your particular strategy. And, as I mentioned, you need to decide on what parameters it should use. Too tight and you're dumped too quick, too loose and you lose too much before it's triggered. That's why some trailing stops are based on some measure of volatility (eg. Average True Range and Guppy count back), but even then, volatility can have spikes that will kick you out anyway.
All IMHO of course
Cheers,
GP