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Saturday, February 6, 2010

Introduction to MACD

by Dennis Cajigas

Moving Average Convergence/Divergence, otherwise known as MACD, was created by Gerald Appel in the 1960s as a way to analyze market momentum and strength. While it fell out of favor in the early 1980s, it experienced a resurgence of popularity with the development of the MACD histogram by Thomas Aspey in 1986. The histogram provided a way to anticipate crossovers in the MACD, providing another method of analysis that gave the MACD a renewed sense of relevance. Traders often use the histogram as a tool to anticipate trend and momentum shifts.

One of the most useful things about the MACD is that it allows traders the ability to identify market trend changes and strength of momentum in a single indicator. It is particularly popular among currency traders.

The MACD represents the difference between two (fast and slow) weighted moving averages of closing prices. The 12-day moving average is commonly used to represent the fast, while the 26-day moving average, the slow. A trigger line, or signal line, is created by smoothing the result with another weighted moving average. Most commonly, the 9-day is used. This creates a centered momentum oscillator, which visually indicates shifts in trend or changes in momentum.

Common Pitfalls
The MACD is a powerful and useful indicator, but it is a lagging indicator. Often there may be a delay between a signal in the MACD and price movement. The MACD may be used in all market condition types, but it is most useful in volatile markets when trend changes more frequently.

Traders should be careful not to mix signals when forming their trade strategies. For example, when entering a momentum-based trade, the exit strategy should be on a momentum indicator rather than a price, time or profit target.

Four Types of Signals

1. Moving Average Crossover. This occurs when the two moving averages (fast and slow) cross. It indicates a potential shift in trend; essentially more buying (or selling) is coming into the market. It is the most common type of signal, but should be reinforced with another type of signal as it can occur fairly often. A three-bar confirmation in the price action or in the MACD histogram can provide a confirmation signal.

In the chart examples that follow, you’ll see two red and blue lines at the bottom, representing the two moving average time periods (fast and slow). The histogram in the middle has a line running through the center, which creates a trigger or signal line.

The histogram visually shows the difference between the moving averages. It also smoothes out fluctuations. I’m using a candlestick chart, with down days designated by red candles and up days by green.

Let’s look at a daily chart of the U.S. dollar in 2009 as an example. In the lower part of the screen, there is a moving average crossover of the12-day and 26-day moving averages, represented by the tan circle. We see the shift in price reflected in the corresponding tan circle in the candlestick chart, as the market starts to decline. There is another crossover as the trend shifts to the positive side in the next set of light blue circles farther to the right of the chart, as buying comes into the market. You see the reflection of the price move in the MACD, and we have continued rallies going forward.

Chart 1, Moving Average Crossover

macd-1

2. Centerline Crossover. This occurs when the MACD moves past the zero line and moves into the opposite territory. That is, going from positive to negative, or negative to positive. It can be combined with other types of indicators to confirm the signal. Traders will often also monitor the slope of the histogram or the two indicator lines to reveal increasing strength or weakness of the market momentum. How quickly is it moving, and how fast and strong?

In the next chart, we see the centerline crossover and the shift from negative to positive. The bars are steadily and slowly increasing, which shows more buying coming in, and increased positive momentum (represented by the beige ellipses). Notice the extreme slope on the histogram and the corresponding gaps in price action on the chart. A bit of a bullish pennant formation is seen in the price chart.

The purple bars (histograms) move below the zero line and then above as price rises (tan circles). We then see a negative crossover to the right on the chart. As the length of the histogram increases, the slope increases and we see that in bearish price action (indicated by the light blue circles).

macd-picture2

3. Positive/Negative Divergence. This occurs when the strength or weakness of the MACD differs from the relative price action of the market. It is the least common of all the MACD signals, but is often the most reliable of the MACD signals, indicating a major trend shift.

On Chart 3, we see a high occur, and then a lower high on the MACD histogram, indicating weakening or exhausting buying pressure. The MACD is telling us the rally we are seeing is a weak one (see the orange line at top right). Afterward, we see a drop in price reinforced by the drop in the MACD and MACD histogram. The market’s bottom should be indicated by a drop in momentum.

Chart 3, Positive/Negative Divergence

macd3

4. Multiple Indicator Signal. If you have one indicator producing a signal, you might want to reinforce it. As the MACD crossover goes from bearish to bullish in Chart 4, it is reinforced later by a centerline crossover. We thus have two signals combining to reinforce the trade. We see an increasing histogram, indicating increasing bullish momentum entering into the market, and price action confirms the bullish shift. Within the light blue ellipses, we see multiple indicators. The MACD crossover gives indications of a possible shift, and the centerline crossover indicates increasing momentum.

Chart 4, Multiple Indicator Signal

macd-4

Looking at a more current chart of the U.S. dollar in early 2010, the blue ellipse represents a positive (bullish) moving average crossover and it is reinforced by a positive centerline crossover. These bullish MACD signals are reflecting the shift in price action and you can see market trend change indicated by the blue ellipse on the price chart.

The beige rectangle is overlain on another positive moving average crossover and the MACD signaled a momentum shift within an already established trend. The MACD signal indicated a rally extension (micro-trend change) as opposed to a major trend shift.

U.S. Dollar Index, Early 2010

macd5-dennis2

This is just a brief introduction to MACD, and I encourage you to do further research and to contact me with questions on how you might apply these techniques to your market analysis. I find the MACD to be useful for all markets to determine momentum and trend shifts.

Dennis G. Cajigas is a Senior Market Strategist with Lind Plus, Lind-Waldock’s broker-assisted division. He can be reached at (866) 631-6216 or by email at dcajigas@lind-waldock.com.

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