Scale the strategy return stream, not one trade's stop distance
Let uₜ be the daily simple return of a fixed, unscaled reference strategy, before the additional overlay costs modeled here. Keep its signal, holdings rule and original sizing definition unchanged. A nonnegative multiplier Lₜ scales that reference exposure. If the reference goes short, its direction stays short; the overlay changes magnitude. It does not create a momentum entry signal.
- ATR position sizing budgets cash against one trade's stop distance. Volatility targeting estimates variation in the whole strategy's periodic returns, including interactions among positions. An account with several positions needs a combined return series or a covariance-aware model.
- A 2× multiplier means twice the reference exposure. It means 200% gross notional only when the reference has 100% gross notional. If the reference already has 150%, a 2× overlay produces 300%; enforce absolute gross, net, margin and concentration limits as well.
- Estimate from the unscaled reference. Feeding the already scaled account returns back into this formula changes the controller and can create oscillating exposure. Keep a separate reference series when testing the overlay.
- Man Group's research describes increasing exposure in calm periods and reducing it in volatile periods. Its historical results differ by asset class. Neither that research nor this arithmetic establishes improved returns for a new TradingView strategy.