Support and resistance share enough common characteristics to effectively be mirror images of each other.
Highs and Lows
Support can be established with the previous reaction lows, while resistance can be established by using the previous reaction highs.
The above chart for Halliburton (HAL) shows a large trading range between Dec-99 and Mar-00. Support was established with the October low around 31. In December, the stock returned to support in the mid-thirties and formed a low around 33. Finally, in February, the stock again returned to the support scene and formed a low around 32 1/2.
After each bounce off support, the stock traded all the way up to resistance. Resistance was first established by the September support break at 42.5. After a support level is broken, it can turn into a resistance level. From the October lows, the stock advanced to the new support-turned-resistance level around 42.5. When the stock failed to advance past 42.5, the resistance level was confirmed. The stock subsequently traded up to 42.5 two more times after that and failed to surpass resistance both times.
Support Equals Resistance
Another principle of technical analysis stipulates that support can turn into resistance and vice versa. Once the price breaks below a support level, the broken support level can turn into resistance. The break of support signals that the forces of supply have overcome the forces of demand. Therefore, if the price returns to this level, there is likely to be an increase in supply, and hence resistance.
The other turn of the coin is resistance turning into support. As the price advances above resistance, it signals changes in supply and demand. The breakout above resistance proves that the forces of demand have overwhelmed the forces of supply; if the price returns to this level, there is likely to be an increase in demand and support will be found.
In this example of the NASDAQ 100 Index ($NDX), the stock broke resistance at 935 in May-97 and traded just above this resistance level for over a month. As the stock remained above resistance, 935 was established as a new support level. The stock subsequently rose to 1150, but then fell back to test support at 935. After the second test of support at 935, this level is well established.
In the above example from PeopleSoft (PSFT), we can see that support can turn into resistance and then back into support. PeopleSoft found support at 18 from Oct-98 to Jan-99 (green oval), but broke below support in Mar-99 as the bears overpowered the bulls. When the stock rebounded (red oval), there was still overhead supply at 18 and resistance was met from Jun-99 to Oct-99.
Where does this overhead supply come from? Demand was obviously increasing around 18 from Oct-98 to Mar-99 (green oval). Therefore, there were a lot of bullish buyers of the stock around 18. When the price declined below 18 and fell to around 14, many of these (now unhappy) bulls were probably still holding the stock. This left a supply overhang (commonly known as resistance) around 18. When the stock rebounded to 18, many of the green-oval-bulls probably took the opportunity to sell and “escape” with little to no loss. When this supply was exhausted, the demand was able to overpower supply and advance above resistance at 18.
Trading ranges can play an important role in determining whether support and resistance function as turning points or continuation patterns. A trading range is a period of time when prices move within a relatively tight range. This signals that the forces of supply and demand are evenly balanced. When the price breaks out of the trading range, above or below, it signals that a winner has emerged. A break above is a victory for the bulls (demand) and a break below is a victory for the bears (supply).
After an extended advance from 27 to 64, WorldCom (WCOM) entered into a trading range between 55 and 63 for about 5 months. There was a false breakout in mid-June when the stock briefly poked its head above 62 (red oval). This did not last long and a gap down a few days later nullified the breakout (black arrow). The stock then proceeded to break support at 55 in Aug-99 and trade as low as 50. Here is another example of support turning to resistance, as the stock bounced off 55 two more times before heading lower. While this does not always happen, a return to the new resistance level offers a second chance for longs to get out and shorts to enter the fray.
Support and Resistance Zones
Because technical analysis is not an exact science, it is useful to create support and resistance zones. This is contrary to the strategy mapped out for Lucent Technologies (LU), but it is sometimes the case. Each security has its own characteristics, and analysis should reflect the intricacies of the security. Sometimes, exact support and resistance levels are best, and, sometimes, zones work better. Generally, the tighter the range, the more exact the level. If the trading range spans less than 2 months and the price range is relatively tight, then more exact support and resistance levels are best suited. If a trading range spans many months and the price range is relatively large, then it is best to use support and resistance zones. These are only meant as general guidelines, and each trading range should be judged on its own merits.
Returning to the analysis of Halliburton (HAL), we can see that the November high of the trading range (32 to 44) extended more than 20% past the October low, making the range quite large relative to the price. Because the September support break forms our first resistance level, we are ready to set up a resistance zone after the November high is formed, probably around early December. At this point though, we are still unsure if a large trading range will develop. The subsequent low in December, which was just higher than the October low, offers evidence that a trading range is forming, and we are ready to set the support zone. As long as the stock trades within the boundaries set by the support and resistance zone, we will consider the trading range to be valid. Support may be looked upon as an opportunity to buy, and resistance as an opportunity to sell.
Identification of key support and resistance levels is an essential ingredient to successful technical analysis. Even though it is sometimes difficult to establish exact support and resistance levels, being aware of their existence and location can greatly enhance analysis and forecasting abilities. If a security is approaching an important support level, it can serve as an alert to be extra vigilant in looking for signs of increased buying pressure and a potential reversal. If a security is approaching a resistance level, it can act as an alert to look for signs of increased selling pressure and potential reversal. If a support or resistance level is broken, it signals that the relationship between supply and demand has changed. A resistance breakout signals that the bulls (demand) have gained the upper hand and a support break signals that the bears (supply) have won the battle.