Think of prices for financial instruments as a result of a head-to-head battle between a bull (the buyer) and a bear (the seller). Bulls push prices higher, and bears lower them. The direction prices actually move shows who wins the battle.

Support is a level at which bulls (i.e., buyers) take control over the prices and prevent them from falling lower.

Resistance, on the other hand, is the point at which sellers (bears) take control of prices and prevent them from rising higher. The price at which a trade takes place is the price at which a bull and bear agree to do business. It represents the consensus of their expectations.

Support levels indicate the price where the most of investors believe that prices will move higher. Resistance levels indicate the price at which the most of investors feel prices will move lower.

But investor expectations change with the time, and they often do so abruptly. The development of support and resistance levels is probably the most noticeable and reoccurring event on price charts. The breaking through support/resistance levels can be triggered by fundamental changes that are above or below investor’s expectations (e.g., changes in earnings, management, competition, etc.) or by self-fulfilling prophecy (investors buy as they see prices rise). The cause is not so significant as the effect: new expectations lead to new price levels. There are support/resistance levels, which are more emotional.

Supply and demand

There is nothing mysterious about support and resistance: it is classic supply and demand. Remembering ’Econ 101’ class, supply/demand lines show what the supply and demand will be at a given price.

The supply line shows the quantity (i.e., the number of shares) that sellers are willing to supply at a given price. When prices increase, the quantity of sellers also increases as more investors are willing to sell at these higher prices. The demand line shows the number of shares that buyers are willing to buy at a given price. When prices increase, the quantity of buyers decreases as fewer investors are willing to buy at higher prices.

At any given price, a supply/demand chart shows how many buyers and sellers there are. In a free market, these lines are continually changing. Investor’s expectations change, and so do the prices buyers and sellers feel are acceptable. A breakout above a resistance level is evidence of an upward shift in the demand line as more buyers become willing to buy at higher prices. Similarly, the failure of a support level shows that the supply line has shifted downward.

The foundation of most technical analysis tools is rooted in the concept of supply and demand. Charts of prices for financial instruments give us a superb view of these forces in action.

Traders’ remorse

After a support/resistance level has been broken through, it is common for traders to ask themselves about to what extent new prices represent the facts. For example, after a breakout above a resistance level, buyers and sellers may both question the validity of the new price and may decide to sell. This creates a phenomenon that is referred to as “traders’ remorse”: prices return to a support/resistance level following a price breakout.

The price action following this remorseful period is crucial. One of two things can happen: either the consensus of expectations will be that the new price is not warranted, in which case prices will move back to their previous level; or investors will accept the new price, in which case prices will continue to move in the direction of the breaking through.

In case number one, following traders’ remorse, the consensus of expectations is that a new higher price is not warranted, a classic “bull trap” (or false breakout) is created. For example, the prices broke through a certain resistance level (luring in a herd of bulls who expected prices to move higher), and then prices dropped back to below the resistance level leaving the bulls holding overpriced stock. Similar sentiment creates a bear trap. Prices drop below a support level long enough to get the bears to sell (or sell short) and then bounce back above the support level leaving the bears out of the market.

The other thing that can happen following traders’ remorse is that investors expectations may change causing the new price to be accepted. In this case, prices will continue to move in the direction of the penetration.

A good way to quantify expectations following a breakout is with the volume associated with the price breakout. If prices break through the support/resistance level with a large increase in volume and the traders’ remorse period is on relatively low volume, it implies that the new expectations will rule (a minority of investors are remorseful). Conversely, if the breakout is on moderate volume and the “remorseful” period is on increased volume, it implies that very few investor expectations have changed and a return to the original expectations (i.e., original prices) is warranted.

Resistance becomes support

When a resistance level is successfully broken through, that level becomes a support level. Similarly, when a support level is successfully broken through, that level becomes a resistance level.

The reason for it is that a new “generation” of bulls appears, who refused to buy when prices were low. Now they are anxious to buy at any time the prices return to the previous level. Similarly, when prices drop below a support level, that level often becomes a resistance level that prices have a difficult time breaking through. When prices approach the previous support level, investors seek to limit their losses by selling.