Principles of Trend Following Trading

What is Trend Following?

Trend following is a trading strategy that capitalizes on the tendency of prices to move consistently in one direction, known as a trend. Based on the empirical observation that stocks going up tend to keep going up, and stocks going down tend to keep going down, the strategy involves buying during an uptrend and reducing holdings or selling during a downtrend.

The core of this approach is that it does not attempt to predict the future. It doesn't try to guess how high a price will go; instead, it identifies an already established direction and follows it. This means entries and exits can be late, but the goal is to capture the middle portion of a significant price movement.

Trend following is closer to a systematic approach because it operates based on predefined rules rather than individual intuition. The principle is to set entry conditions, exit conditions, and stop-loss criteria in advance and execute them strictly.

Tools and Calculations for Defining Trends

The simplest tool for objectively defining a trend is the moving average. For example, after calculating the average closing price over the past N days, if the current price is above that average, it's considered an uptrend; if it's below, it's a downtrend. If the 20-day average is 50 and the current stock price is 55, the short-term trend is considered upward.

To obtain more stable signals, two moving averages of different periods are sometimes used in conjunction. For instance, if the 50-day average crosses above the 200-day average, it's interpreted as a long-term upward reversal (commonly known as a golden cross); if it crosses below, it's a downward reversal (a death cross). Longer periods result in slower signals but are less susceptible to noise.

Indicators like MACD or price channels (breaking recent N-day highs or lows) are also used for the same purpose. The commonality among all these tools is that they reduce subjective judgment by using numerical criteria to determine the beginning and end of a trend.

Criteria for Interpreting Signals

In trend following, the most important interpretation criterion is exiting, rather than entering. Even if you've entered an uptrend, if the price falls below the baseline, you exit, considering the trend to be over. Whether it's a profit or a loss, you follow the rule if it indicates an exit.

The strength of the trend is also considered. Periods where the price moves significantly away from the average line with increasing trading volume are read as a sign that the trend is strong, while sideways periods where the price fluctuates around the average line are seen as a sign of no trend. Trend-following signals often fail in sideways markets.

This article is for educational purposes, explaining the principles of reading signals, rather than recommending specific trades. It should be read with the understanding that the appropriate period settings for the same indicator can vary depending on the stock and market environment.

Practical Application and Money Management

Trend following only works effectively when accompanied by a stop-loss. At the time of entry, a stop-loss price is set, and if it turns out the trend was not valid, the position is closed with a small loss. For example, if you buy at $100 and set a stop-loss at $92, the maximum loss from a single failed trade is limited to $8.

Profits are allowed to run as long as the trend is alive. This structure, where losses are kept small and profits are allowed to grow, means that overall performance can be positive even if the win rate is less than 50%. For instance, if you are right 4 out of 10 times, and your average win is +25 while your average loss is -8, the total outcome will be positive.

Whether in the Korean market or the US market, the principles are the same, but transaction costs and volatility differ. Frequent trading can lead to accumulated fees and taxes, so considering both signal frequency and costs when setting periods is crucial in practice.

Pitfalls and Limitations

The biggest weakness of trend following is sideways markets. In periods without a clear trend, prices fluctuate above and below the baseline, leading to repeated buy and exit signals, and accumulating small losses in what is known as a whipsaw effect. Statistically, trend following tends to have a low win rate, with large profits occurring infrequently but in concentrated bursts.

Indicators are inherently lagging. Moving averages, being averages of past prices, always signal trend reversals one step late. Therefore, it must be accepted that they are tools for capturing the middle portion of a trend, not for picking tops and bottoms.

Over-optimizing period settings to past data is another pitfall. There's no guarantee that settings that worked best in a specific historical period will continue to work in the future, and such over-optimization can lead to unverified confidence.

Key Takeaways

Trend following is a rules-based approach that follows confirmed trends rather than predicting them, using objective tools like moving averages and breakouts to determine the start and end of a trend. Exit and stop-loss rules are more critical to performance than entry rules.

Because it's structured to cut losses short and let profits run as long as the trend is alive, it compensates for a low win rate with large profits. It is meaningful to operate this strategy with proper money management, while being aware of its three limitations: whipsaws in sideways markets, the lagging nature of indicators, and over-optimization.