OutsideBar — Outside Bar

A bar whose range contains the previous bar’s entirely: an expansion that took out both sides. Often a reversal, always a widening of the trading range. Returns 1 when present.

Signature

OutsideBar(lookback, on=<source>)

Argument	Type	Required	Notes
lookback	int Param	Yes	Pinned at 1. Bounds 1–1.
on=	symbol	No	Source symbol. Defaults to the trade symbol. Reads high and low.

Formula

$$ \text{OutsideBar} = 1 \text{ when } H_t \ge H_{t-1} \text{ and } L_t \le L_{t-1} $$

Warmup

One bar of state.

Reading the value

ob.value
ob > 0

Example

class OutsideBarReversal(Strategy):
    """Trade the direction an outside bar closed."""
    trade = Symbol()
    sizing = FixedCapital()

    def execute(self):
        ob = OutsideBar(1, on=self.trade)
        sma = SMA(50, on=self.trade)
        if ob.value > 0 and self.trade.close > sma.value and self.trade.is_flat:
            self.buy(self.trade, reason="Outside bar up")
        if self.trade.close < sma.value and self.trade.is_long:
            self.sell(self.trade, self.trade.position, reason="Trend lost")

Notes

• Range-based, unlike Engulfing, which compares bodies. They fire on different bars and mean different things.
• Proven by an assert-via-trade run on SPY daily (matched a strategy-side reference exactly on every bar; zero alarm trades).