Operator brief · 441

System Lock sits where you put it, so the lock rate is partly a statement about your settings.

The key idea

What lock actually is

A threshold in the configuration, not a law of the market.

System Lock triggers at a drawdown worse than a defined level — in the standard configuration, worse than −40% from Equity Peak High. Locked paths stop trading and are excluded from target completions. That level is a choice made by whoever configured the system, and every survivability figure downstream is computed relative to it. The lock rate answers a conditional question: given that trading stops at this depth, how often is that depth reached?

FigureMove the boundary, move the reported lock rate

Schematic. Same strategy, same risk, four different boundary settings.

The manoeuvre

The easiest way to improve a ruin number is to move the finish line.

Because the figure is conditional on the threshold, deepening the threshold improves it instantly and requires no change to the strategy, the sizing, or the discipline. A configuration that locks at −55% will report a materially lower lock rate than the same configuration locking at −40%, and both figures are arithmetically correct. Nothing about the account got safer. The boundary at which the account is declared dead simply moved further away, which means the paths formerly counted as failures are now counted as survivors carrying very deep drawdowns. Whether that reclassification is honest depends entirely on whether an account at that depth could realistically continue — a judgement about capital and temperament, not something the simulation can settle.

Where it hides

Removing the boundary entirely reports a lock rate of zero.

The limiting case is worth stating plainly, because it is the one most likely to be encountered in someone else's marketing. A system with no shutdown boundary cannot record a lock, and will truthfully report zero lock probability. That figure conveys no information about safety whatsoever — it describes the absence of a rule, not the presence of resilience. Whenever a ruin or lock figure appears without the threshold it was computed against, the figure is unreadable, and a favourable one should raise the question rather than settle it.

The consequence for reading

A lock rate is only comparable against the same boundary.

This makes lock rate a poor number to compare across systems and an excellent one to compare across configurations of the same system. Two accounts locking at different depths cannot have their rates placed side by side; the comparison is between two different questions. Within one configuration, held constant, the rate is genuinely informative — it will move when sizing changes, when the tier profile changes, or when the branch mix changes, and each of those movements means something real.

Choosing the boundary

Set it where continuing would be irrational, not where it flatters the output.

The threshold should be set by the same reasoning that sets any predefined response: at the depth beyond which continuing to trade the current configuration is no longer a defensible use of the capital. That depth follows from how much of the account can be lost while recovery remains plausible, and from what the capital is for. It should be chosen before the survivability figures are run, because a threshold chosen afterwards will be chosen partly to make the numbers look better, and everyone involved will know it. The sequence matters more than the specific level chosen: a defensible threshold set first and measured second is worth more than a better-looking one arrived at by iteration against the output.

The pairing

Lock rate is meaningless beside deep-drawdown behaviour.

Because a deeper boundary converts locked paths into surviving ones, lock rate must always be read alongside the drawdown distribution rather than on its own. A configuration reporting a low lock rate and a heavy cluster of paths sitting just short of the boundary is not a safe configuration — it is one whose boundary is generously placed. The pair of readings together is honest; either one alone can be arranged to look reassuring.

Connected inside MARS

Monte Carlo Survivability →

Drawdown Percentiles →

Risk Gate Map →

Monte Carlo Lab →

Every brief documents the same shipped system.

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