2011-07-29 17:56:13
The concepts of support and resistance are undoubtedly two of the most highly discussed attributes of technical analysis and they are often regarded as a subject that is complex by those who are just learning to trade. This article will attempt to clarify the complexity surrounding these concepts by focusing on the basics of what traders need to know. You'll learn that these terms are used by traders to refer to price levels on charts that tend to act as barriers from preventing the price of an asset from getting pushed in a certain direction.
At first the explanation and idea behind identifying these levels seems easy, but as you'll find out, support and resistance can come in various forms and it is much more difficult to master than it first appears. (To learn more, read Analyzing Chart Patterns and Basics Of Technical Analysis.)
The Basics
Most experienced traders will be able to tell many stories about how certain price levels tend to prevent traders from pushing the price of an underlying asset in a certain direction. For example, assume that Jim was holding a position in Amazon.com (AMZN) stock between March and November 2006 and that he was expecting the value of the shares to increase. Let's imagine that Jim notices that the price fails to get above $39 several times over the past several months, even though it has gotten very close to moving above it. In this case, traders would call the price level near $39 a level of resistance. As you can see from the chart below, resistance levels are also regarded as a ceiling because these price levels prevent the market from moving prices upward.
Figure 1
On the other side of the coin, we have price levels that are known as support. This terminology refers to prices on a chart that tend to act as a floor by preventing the price of an asset from being pushed downward. As you can see from the chart below, the ability to identify a level of support can also coincide with a good buying opportunity because this is generally the area where market participants see good value and start to push prices higher again.
Figure 2
Trendlines
In the examples above, you've seen a constant level prevent an asset's price from moving higher or lower. This static barrier is one of the most popular forms of support/resistance, but the price of financial assets generally trends upward or downward so it is not uncommon to see these price barriers change over time. This is why understanding the concepts of trending and trendlines is important when learning about support and resistance. When the market is trending to the upside, resistance levels are formed as the price action slows and starts to pull back toward the trendline. This occurs as a result of profit taking or near-term uncertainty for a particular issue or sector. The resulting price action undergoes a "plateau" effect or slight drop-off in stock price, creating a short-term top. (To learn more, read Track Stock Prices With Trendlines and Short-, Intermediate- and Long-Term Trends.)
Many traders will pay close attention to the price of a security as it falls toward the broader support of the trendline because historically, this has been an area that has prevented the price of the asset from moving substantially lower. For example, as you can see from the Newmont Mining Corp (NEM) chart below, a trendline can provide support for an asset for several years. In this case, notice how the trendline propped up the price of Newmont's shares for an extended period of time.
Figure 3
On the other hand, when the market is trending to the downside, traders will watch for a series of declining peaks and will attempt to connect these peaks together with a trendline. When the price approaches the trendline, most traders will watch for the asset to encounter selling pressure and may consider entering a short position because this is an area that has pushed the price downward in the past. (To learn more, check out Peak-and-Trough Analysis.)
The support/resistance of an identified level, whether discovered with a trendline or through any other method, is deemed to be stronger the more times that the price has historically been unable to move beyond it. Many technical traders will use their identified support and resistance levels to choose strategic entry/exit prices because these areas often represent the prices that are the most influential to an asset's direction. Most traders are confident at these levels in the underlying value of the asset so the volume generally increases more than usual, making it much more difficult for traders to continue driving the price higher or lower.
Round Numbers
Another common characteristic of support/resistance is that an asset's price may have a difficult time moving beyond a round price level such as $50. Most inexperienced traders tend to buy/sell assets when the price is at a whole number because they are more likely to feel that a stock is fairly valued at such levels. Most target prices/stop orders set by either retail investors or large investment banks are placed at round price levels rather than at prices such as $50.06. Because so many orders are placed at the same level, these round numbers tend to act as strong price barriers. If all the clients of an investment bank put in sell orders at a suggested target of, for example, $55, it would take an extreme number of purchases to absorb these sales and, therefore, a level of resistance would be created.
Moving Averages
Most technical traders incorporate the power of various technical indicators, such as moving averages, to aid in predicting future short-term momentum, but these traders never fully realize the ability these tools have for identifying levels of support and resistance. As you can see from the chart below, a moving average is a constantly changing line that smooths out past price data while also allowing the trader to identify support and resistance. Notice how the price of the asset finds support at the moving average when the trend is up, and how it acts as resistance when the trend is down. Most traders will experiment with different time periods in their moving averages so that they can find the one that works best for this specific task. (To read more, see Exploring Oscillators And Indicators and Trading Psychology And Technical Indicators.)
Figure 4
Other Indicators
In technical analysis, many indicators have been developed for to identify barriers to future price action. These indicators seem complicated at first and it often takes practice and experience to use them effectively. Regardless of an indicator's complexity, however, the interpretation of the identified barrier should be consistent to those achieved through simpler methods.
For example, the Fibonacci retracement tool is a favorite among many short-term traders because it clearly identifies levels of potential support/resistance. The reasoning behind how this indicator calculates the various levels of support and resistance is beyond the scope of this article, but notice in Figure 5 how the identified levels (dotted lines) are barriers to the short-term direction of the price. (For more on this tool, see What is Fibonacci retracement, and where do the ratios come from?, Advanced Fibonacci Applications and Fibonacci And The Golden Ratio.)
Figure 5
Conclusion
Determining future levels of support can drastically improve the returns of a short-term investing strategy because it gives traders an accurate picture of what price levels should prop up the price of a given security in the event of a correction. Conversely, foreseeing a level of resistance can be advantageous because this is a price level that could potentially harm a long position because it signifies an area where investors have a high willingness to sell the security. As mentioned above, there are several different methods to choose when looking to identify support/resistance, but regardless of the method, the interpretation remains the same - it prevents the price of an underlying from moving in a certain direction.
by Casey Murphy
Casey Murphy is the senior analyst at Investopedia.com and is a graduate of the University of Alberta School of Business. He specializes in technical analysis and is dedicated to uncovering profitable trading opportunities. Click here to join Casey in Investopedia's free stock picking community.