Percentage Price Oscillator: A MACD You Can Compare Across Stocks

Put the MACD of a ₹3,000 stock next to the MACD of a ₹150 stock and the comparison is close to meaningless. The pricier share will almost always show the bigger number, simply because its moving averages sit further apart in rupee terms. The percentage price oscillator, or PPO, fixes exactly that. It takes the same gap between two moving averages and expresses it as a percentage, so a reading on one stock means the same thing on any other.

If you already use MACD, most of the PPO will feel familiar. The lines look alike and the signals are read the same way. What changes is the scale, and that small change opens up a few uses MACD can’t handle well. We will walk through the formula, how to read it, and several worked examples with round, made-up numbers so the arithmetic is easy to follow.

In this article

1. What the percentage price oscillator measures
2. The PPO formula, step by step
3. Worked example 1: two stocks, two very different prices
4. Worked example 2: the same stock after a big run
5. How to read the PPO line and the zero line
6. Signal line crossovers and the histogram
7. Filtering signals with the zero line
8. Comparing momentum and volatility across stocks
9. Divergence on the PPO
10. Where the PPO falls short
11. PPO or MACD: which should you use?
12. A simple way to put the PPO to work

What the percentage price oscillator measures

StockCharts’ ChartSchool describes the PPO as a momentum oscillator that measures the difference between two moving averages as a percentage of the larger moving average. In plain words: how far is the short-term average above or below the long-term average, in percent?

That is the whole idea. A fast average running well above a slow one means price has been rising quickly in the recent past. A fast average sinking below the slow one means the opposite. The PPO just puts a percentage on that distance.

Like MACD, it comes with three parts on the chart:

• The PPO line, the percentage gap between the two averages.
• The signal line, a slower average of the PPO line itself.
• The histogram, the difference between the PPO line and the signal line.

There is also a zero line, or centerline, which the PPO crosses whenever the two underlying averages cross each other.

The PPO formula, step by step

The standard settings are 12, 26 and 9, the same as MACD. Both StockCharts and Investopedia’s PPO explainer give the formula like this:

• PPO = (12-period EMA − 26-period EMA) ÷ 26-period EMA × 100
• Signal line = 9-period EMA of the PPO
• PPO histogram = PPO − signal line

EMA here is the exponential moving average, which gives more weight to recent prices than a simple average does. StockCharts notes that closing prices are used to build the averages, so PPO signals should be judged against closing prices too, not an intraday spike.

Notice that the numerator, 12 EMA minus 26 EMA, is exactly the MACD line. So another way to say it: the PPO is MACD divided by the slower average, times 100. Investopedia puts the practical meaning neatly. Whatever the stock’s price, a PPO of 10 means the short-term average is 10% above the long-term average.

The 12/26/9 settings are not sacred. StockCharts points out they can be changed to suit a trader’s preference. Shorter periods make the line twitchier; longer ones smooth it out and make it slower to react.

Worked example 1: two stocks, two very different prices

Take two hypothetical NSE-listed stocks on the same day.

	Stock A	Stock B
12-day EMA	₹2,550	₹260
26-day EMA	₹2,500	₹250
MACD (12 EMA − 26 EMA)	₹50	₹10
PPO (MACD ÷ 26 EMA × 100)	2.0	4.0

Look at MACD alone and Stock A seems to have five times the momentum, 50 against 10. That’s an illusion created by price. Stock A’s fast average is only 2% above its slow average. Stock B’s is 4% above. On a like-for-like basis, Stock B is the one moving with more force.

This is the single most useful thing the PPO does. If you scan a watchlist that mixes a ₹4,000 IT name with a ₹90 PSU bank, MACD values can’t be ranked against each other. PPO values can.

MACD tells you the gap between two averages in rupees. The PPO tells you the same gap in percent, and percent is the only unit that travels across stocks.

Worked example 2: the same stock after a big run

The price problem also shows up within a single stock over time. StockCharts makes this point with an example of a stock climbing from 20 to 100: MACD values at the low end of that range are naturally much smaller than at the high end, even when momentum is similar. The PPO solves it by staying in percentage terms.

Here’s a hypothetical version. A stock rallies from ₹200 to ₹800 over two years.

• Early on, near ₹200: 12-day EMA ₹206, 26-day EMA ₹200. MACD = ₹6. PPO = 6 ÷ 200 × 100 = 3.0.
• Later, near ₹800: 12-day EMA ₹816, 26-day EMA ₹800. MACD = ₹16. PPO = 16 ÷ 800 × 100 = 2.0.

MACD went from 6 to 16, which looks like momentum nearly tripled. The PPO went from 3.0 to 2.0. In relative terms the stock is actually trending less forcefully than it did at the start. If you were drawing trendlines or comparing peaks on MACD across that whole run, you’d get a distorted picture. On the PPO, a high from two years ago can be compared fairly with today’s.

How to read the PPO line and the zero line

The basic reading is simple, and both sources agree on it:

• PPO above zero: the 12-period EMA is above the 26-period EMA. That supports an uptrend.
• PPO below zero: the short average is below the long one. That points to a downtrend.
• The further the line moves from zero, the faster the short average is pulling away, and StockCharts reads that as stronger momentum in that direction.

A centerline crossover happens when the PPO moves from negative to positive (traders read it as bullish) or from positive to negative (bearish). Since the PPO is zero exactly when the two EMAs are equal, a centerline cross is really just a 12/26 EMA crossover shown on a different panel.

Signal line crossovers and the histogram

The more frequent signal comes from the PPO crossing its own 9-period signal line. Investopedia describes the common reading: a cross above the signal line from below is treated as a buy signal, and a cross below from above as a sell signal.

The histogram makes those crossovers easier to see coming. It is positive when the PPO is above the signal line and negative when it is below. When the bars shrink towards zero, the two lines are converging, and StockCharts notes the histogram can be used to anticipate signal line crossovers.

Worked example 3: reading three days of the histogram

Suppose a stock’s readings over three sessions look like this (hypothetical numbers):

Day	PPO	Signal line	Histogram (PPO − signal)
Day 1	1.8	1.2	+0.6
Day 2	1.5	1.3	+0.2
Day 3	1.2	1.3	−0.1

On Day 1 the PPO is comfortably above the signal line. On Day 2 the histogram has shrunk from 0.6 to 0.2: momentum is fading, even though the PPO is still positive and the trend, by the zero-line test, is still up. By Day 3 the histogram has flipped negative, which is the signal line crossover.

What does that tell us? Only that upward momentum has cooled. The PPO is still above zero, so the short average is still above the long one. A trader who respects the bigger trend might treat Day 3 as a reason to tighten a stop rather than to go short.

Filtering signals with the zero line

Taking every crossover blindly is an easy way to rack up small losses with any oscillator. Investopedia mentions a filter some traders use: take signal-line buy signals only when the PPO is above zero, and when it is below zero, either ignore buy signals or look only for short-sell signals.

In practice this pairs the two types of signal. The zero line sets the direction you’re willing to trade. The signal line crossover times the entry within that direction. It cuts the number of trades sharply, and the ones it throws away are mostly attempts to catch a falling stock.

Worked example 4: one filtered trade

A hypothetical stock has a PPO of +1.4, and the line has dipped below its signal line during a pullback. A few sessions later the PPO turns up and crosses back above the signal line, with the PPO still positive. Under the filter, that’s a valid long entry.

Say the trader buys at ₹1,000 with a stop at ₹960, so ₹40 of risk per share. With ₹2,000 of total risk allowed on the trade, the position is 2,000 ÷ 40 = 50 shares, worth ₹50,000. The PPO helped pick the moment; the stop and the sizing decide how much it can hurt if the signal fails. If you want more on that second half, our guide to risk management in trading covers position sizing in detail.

Now flip it. If the same crossover happened with the PPO at −1.4, the filter says skip it. The short average is still below the long one, and a bounce in a downtrend is the kind of signal that fails often.

Comparing momentum and volatility across stocks

Because PPO values sit on a common percentage scale, you can line up several stocks and compare them directly. Two practical uses come out of this.

Momentum ranking. Investopedia’s illustration is simple: if one stock has a PPO of 3 and another a PPO of 1, the first has had more recent strength, since its short average is further above its long average. On a sector watchlist, sorting by PPO gives you a quick view of which names are leading.

A rough volatility read. Look at how wide a stock’s PPO range has been over the past year. Investopedia’s example compares a stock whose PPO ranged from 3.25 to −5.80 (a 9.05-point range) with one ranging from 2.65 to −4.5 (a 7.15-point range), and concludes the first was more volatile. StockCharts does the same with two stocks in one industry group, one with an eight-point range and one with a five-point range.

Worked example 5: two banks on one watchlist

Say over the last year, Bank X’s PPO swung between +5.0 and −4.0, a 9-point range. Bank Y’s swung between +3.0 and −2.5, a 5.5-point range. Bank X has had the more violent momentum swings. Today, Bank X reads +0.8 and Bank Y reads +2.2, so Bank Y currently has the stronger upward momentum despite being the calmer stock overall.

Investopedia is careful to call this a very rough comparison of volatility, and it’s right to. The PPO only measures the distance between two moving averages, not actual day-to-day price movement. For a proper volatility number you would still want something like ATR or standard deviation.

A wide PPO range says a stock’s trend speeds up and slows down sharply. It does not say how much the price jumps around inside a single day.

Divergence on the PPO

Divergence works the same way as on any momentum oscillator. If price makes a higher high but the PPO makes a lower high, upward momentum may be fading. If price makes a lower low while the PPO makes a higher low, the sellers may be losing steam.

Here the PPO has a quiet edge over MACD for long time frames. Because MACD scales with price, a stock that has doubled will tend to print higher MACD peaks even when momentum is unchanged, which can hide a genuine divergence. StockCharts shows a case where MACD broke above its earlier highs but the PPO did not. Comparing peaks in percentage terms avoids that trap.

One caution from Investopedia is worth keeping in front of you: divergence is not a timing signal. It can last a long time and does not always end in a reversal.

Where the PPO falls short

No indicator earns a place on the chart without knowing its weak spots. The main ones:

• Whipsaws in sideways markets. Investopedia’s example: price rises, then moves sideways. The two EMAs converge during the pause, which can trigger a signal line crossover and even a centerline crossover, though price hasn’t actually reversed. Several crossovers in a row without a real move usually mean several small losing trades.
• It isn’t built for overbought and oversold. StockCharts notes that PPO movements are, in theory, unlimited. Bounded oscillators like RSI and the Stochastic Oscillator are better suited to spotting stretched conditions. If that’s your goal, our piece on the Stochastic RSI indicator is a better starting point.
• It lags. Every input is a moving average of past prices. As Investopedia puts it, there is nothing inherently predictive in the calculations; they show what has happened.
• It largely repeats MACD. StockCharts says the PPO generates the same signals as MACD, with only subtle differences between the lines at times. Centerline crossovers are identical by construction, since dividing by a positive average doesn’t change where a line crosses zero. Running both on one chart mostly adds clutter.

PPO or MACD: which should you use?

For timing trades on one stock over a few weeks, it barely matters. The signals are largely the same, and plenty of traders happily stick with the MACD indicator they already know.

The PPO earns its keep in three situations:

• When you compare momentum across stocks with very different share prices.
• When you study a stock over a long period in which its price has moved a lot, such as a multi-year multibagger.
• When you compare a stock’s momentum against an index, whose level in points runs far above most share prices.

StockCharts sums up the point well. The PPO levels of an index trading around 11,000 can be compared against those of a stock around 122, because the PPO levels the playing field. MACD can’t do that.

A simple way to put the PPO to work

Here is how we’d fold it into a routine. Add the PPO with default 12/26/9 settings to your daily charts. Use the zero line to decide whether you’re looking for longs or shorts on a stock. Use the signal line crossover, preferably confirmed on a closing basis, to time entries in that direction. And once a week, sort your watchlist by PPO value to see which names are carrying the strongest momentum relative to their own price.

Pair it with something that reads price structure, like support and resistance or volume, and with a stop-loss you set before you enter. Our broader guide to technical analysis for Indian stocks shows how these pieces fit together. The PPO is a good measuring tool. It’s still only one of them.

Disclaimer: This article is for educational purposes only and is not investment advice. All examples use hypothetical numbers. Markets carry risk; please do your own research or consult a SEBI-registered adviser before making investment decisions.