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