PPO - Percentage Price Oscillator
The Percentage Price Oscillator is a percentage-based version of the MACD indicator which was developed by Gerald Appel in the late 70s and is used to indicate both trends and momentum.
The MACD is price-based so it is not possible to directly compare MACD values between different stocks. Since the PPO is percentage-based you can compare any stocks or indices no matter the price levels.
The PPO is based on a PPO line calculated by the percentage difference between a short term EMA of the Close Price and a longer term EMA of the Close Price. A signal line is then generated by applying an EMA to the PPO line. And finally a histogram shows the difference between the PPO Line and the Signal line.
The PPO line will be above 0 when the short term average is higher than the long term average and below 0 when it is lower. So the further away from 0 the more divergent the EMAs. An increasing PPO line indicates upward momentum and a decreasing line indicates downward momentum.
The most common use of PPO is to track crossovers between the Signal line and the PPO line in order to spot turns. Crossovers of the PPO line and the 0 line are also useful.
PPO Line: (12 day EMA - 26 day EMA) / 26 day EMA * 100 (Blue)
Signal Line: 9 day EMA of PPO Line (Red)
PPO Histogram: PPO Line - Signal Line (Orchid)
Sufficient Data for Accuracy
The PPO is based on EMAs which are one of several indicators that include an element of prior data. As such a 26 day EMA based on 50 days of underlying data will be significantly different to a 26 day EMA based on 500 days of data. This site will always include enough data to ensure 'accuracy'.