Every trailing exit pays a visible, irritating cost: the gap between the best price a position reached and the price at which it was finally banked. Traders call it give-back and treat it as leakage to be engineered away. This paper reprices it as what it actually is: an option premium — the recurring cost of keeping the lead-time window open.

Recall the arithmetic of the series. Boundaries live in time; a trail tight enough to surrender almost nothing at the top must, by construction, exit on the first meaningful pause — and meaningful pauses are precisely what the journey between boundaries is made of. Squeeze the give-back toward zero and you have not improved the exit; you have amputated the right tail in time, quietly converting a boundary-seeking system into a scalping system that still believes itself a trend follower.

Our own live evidence base — an excursion ledger recording, for every closed position, the maximum favourable excursion and the final banked result, both in risk units — currently shows a mean give-back near 0.14R across brokers, asset classes, and account sizes from hundreds of dollars to hundreds of millions. The figure is remarkably stable, and its stability is the point: it is the market rent for optionality, and rent is supposed to be boring.

Priced against what it preserves, the premium is cheap. A single boundary-completing trend banks multiples of R that repay dozens of premiums; the ledger’s deepest climbers already demonstrate the asymmetry in miniature. The correct optimisation target is therefore never the premium in isolation — it is net tail capture at statistical sample: total R banked from boundary-breakers minus total premium paid, stratified by regime. Any exit “improvement” that reduces the premium must state which boundary lead-times it forecloses and price that foreclosure honestly.

The discipline in one sentence: pay the rent, keep the option, and audit the trade-off only where it can be seen — at sample, in risk units, never in the emotional currency of a single close that gave some back.