PercentPriceOscillator — Percent Price Oscillator

The Price Oscillator expressed as a percentage of the slow moving average. Same signal, but comparable across instruments and across time.

PercentPriceOscillator is the identifier a strategy writes; Percent Price Oscillator is the label the chart’s indicator picker shows. Single value — .value is the only accessor.

Signature

PercentPriceOscillator(fast_period, slow_period, on=<source>)

Argument	Type	Required	Notes
fast_period	int Param or literal	Yes	Short window. Default 12, bounds 2–50.
slow_period	int Param or literal	Yes	Long window. Default 26, bounds 10–200.
on=	symbol, OHLCV field, or indicator	No	Source. Defaults to the trade symbol’s close.

Formula

$$ \text{PPO}_t = \frac{\text{SMA}_F - \text{SMA}_S}{\text{SMA}_S} \times 100 $$

The numerator is the plain Price Oscillator; dividing by the slow average turns price units into percent. A reading of 1.5 means the fast average sits 1.5% above the slow one — the same statement on a $12 stock and a $600 one.

Warmup

max(fast_period, slow_period) bars — in practice slow_period, since both buffers must be full. Until then it returns 0.

Two arguments, one warmup number

History prefill is sized from the first argument (fast_period) plus one bar, and execute() additionally waits until every indicator’s own window is full. Nothing is computed on a half-filled window; the run just starts later than the prefill number alone suggests.

Reading the value

ppo.value              # percent, e.g. 1.5 means +1.5%
ppo.value_at(1)
ppo > 1.5              # a threshold that travels between instruments
ppo.crossed_above(0)

Example

class PercentOscillatorTrend(Strategy):
    """Enter only when the fast/slow gap is a meaningful percentage."""
    fast = Param(12, min=2, max=50)
    slow = Param(26, min=10, max=200)
    threshold = Param(1, min=1, max=10)
    trade = Symbol()
    sizing = FixedCapital()

    def execute(self):
        ppo = PercentPriceOscillator(self.fast, self.slow, on=self.trade)
        self.stop_loss(2.0)

        if ppo.value > self.threshold and self.trade.is_flat:
            self.buy(self.trade, reason=f"PPO {ppo.value:.2f}%")

        if ppo.value < 0 and self.trade.is_long:
            self.sell(self.trade, self.trade.position, reason="PPO back below zero")

Notes

• This is the version to optimize over. A percentage threshold found on one symbol is at least meaningful on another; the raw PriceOscillator threshold is not.
• The division is not floored. The seeded source divides by the slow SMA directly, with no epsilon guard. On price that is harmless — a slow average of exactly zero cannot happen. Chained onto something that oscillates through zero (PercentPriceOscillator(12, 26, on=some_oscillator)), it can, and there is no protective clamp. Chain onto price-like sources.
• The value is already in percent — do not multiply by 100 again.
• Zero crossings are identical to the Price Oscillator’s, since the denominator is positive for price sources. What changes is only the magnitude scale, which is where the usefulness lives.