The Moving Average Convergence Divergence charts, or MACD charts for short, are a technical indicator that is derived from
more simple moving average. The MACD charts are oscillating indicators, meaning that they move above and below a centerline or zero point. As with other oscillating and momentum indicators, a very high value indicates that
stock is overbought and will likely drop soon. Conversely, a consistently low value indicates that
stock is oversold and is likely to climb.
THE 12-DAY AND 26-DAY EMAS
The MACD charts are based on 3 exponential moving averages, or EMA. These averages can be of any period, though
most common combination, and
one we will focus on, are
12-26-9 MACD charts.
There are 2 parts to
MACD. We will focus first on
first part, which is based on
stock's 12-Day and 26-Day EMA. The 12-Day EMA is
faster EMA while
26-Day is slower.
The logic behind using a faster and slower EMA is that this can be used to gauge momentum. When
faster (in this case 12-Day) EMA is above
slower 26-Day EMA,
stock is in an uptrend, and vice versa. If
12-Day EMA is increasing much faster than
26-Day EMA,
uptrend is becoming stronger and more pronounced. Conversely, when
12-Day EMA starts slowing down, and
26-Day begins to near it,
stock movement's momentum is beginning to fade, indicating
end of
uptrend.
THE MACD LINE The MACD charts use these 2 EMA by taking
difference between them and plotting a new line. Very often, this new line is depicted as a thick black line in
middle chart.
When
12-Day and 26-Day EMA are at
same value,
MACD line is at zero. When
12-Day EMA is higher than
26-Day EMA,
MACD line will be in positive territory. The further
12-Day EMA is from
26-Day EMA,
further
MACD line is from its centerline or zero value.
THE 9-DAY EMA
This line on its own doesn't tell much more than a moving average. It becomes more useful when we take into account its 9-Day EMA. This is
third value when we talk of 12-26-9 MACD charts. Note that
9-Day EMA is an EMA of
MACD line, not of
stock price. This EMA (the thin blue line alongside
MACD line) acts like a normal EMA and smoothes
MACD line.