Use the Ackerman bid sequence: 65%–85%–95%–100% of target

Make four calculated offers that converge on your target with shrinking steps — each concession signals you are approaching your limit.

Why it works

The sequence of decreasing concession sizes (starting at 65% of your target, moving to 85%, 95%, 100%) communicates information nonverbally: the reducing step size signals that each concession costs more, implying you are near your floor. The counterpart experiences the negotiation as extracting hard concessions even when you end at your planned target. Equal-step concessions signal unlimited room; decreasing steps signal a real limit.

How to do it

1. Set your target. Your opening bid is approximately 65% of your target for a buying situation (or 135% for selling — the direction reverses).
2. Second bid: move to ~85% of target. Third: ~95%. Final: 100% — your actual target.
3. Make each subsequent concession visibly smaller, with visible hesitation: the behavioral signal reinforces the numerical signal.
4. Pair the final offer with a non-round number and a small non-monetary concession to further signal a genuine limit.

Evidence

The concession size as a limit-signal mechanism is grounded in research on behavioral cues in negotiation. The specific Ackerman sequence is a practitioner system developed through FBI and commercial application rather than a separately published RCT. (anecdotal)

The Ackerman percentages are practitioner heuristics, not experimentally validated thresholds. The underlying principle — that decreasing concessions signal a genuine limit — has behavioral research support; the specific percentages do not.

Sources

• Voss & Raz (2016), Never Split the Difference

Common mistake

Making large equal concessions throughout — this signals to the counterpart that more is available at each step and extends the negotiation past your actual target.