Spreading names is not a substitute for a ruin bound

Spreading names as a risk habit

Spreading holdings is treated as a popular but undifferentiated risk habit. The archive asks whether that habit actually lowers market risk.

Risk is introduced as the chance of losing part or all of a stake. Diversification, in this reading, means spreading capital across several holdings so each outcome is a smaller share of the final result.

Pooling many trials, as in insurance or a long sequence of coin tosses, is said to make odds easier to estimate because each trial's share of the result falls as the count rises. The same pooling logic is then applied to equities to test whether spreading names still reduces that chance.

What spreading does not remove

Market-wide declines are treated as systematic risk that spreading names does not remove. Idiosyncratic risk, a name-specific or sector-specific shock, may shrink only if holdings stay weakly related.

Those relationships tighten when prices trend together. Correlation instability is that tendency, and it weakens the independence assumed by spreading names.

When risk is defined as spreading

Defining risk through diversification is said to make the link between risk and spreading unmeasurable. The boundary between idiosyncratic risk and systematic risk is left unclear.

A given-back gain is still a loss

A gain that is later fully given back is framed as a real loss, not a wash. That example is used to show mental accounting around risk.

Expected value as a control identity

Expected value per trade is written as win probability times average win minus loss probability times average loss. Those inputs are described as unstable but still usable as a control identity.

The identity is used as a filter on whether a loss-and-size policy can stay bounded before entry.

A bound set before entry

A per-trade loss cap, illustrated at 3%, is offered so average loss cannot exceed that bound. Analysis is the scale, while position sizing and risk limits are the weights that can be set before entry.

Risk of ruin is the chance that a run of losses exhausts the account. It is treated here as the reason to cap stop distance and exposure from equity before a trade is placed.

Spreading as loss avoidance

Avoiding realized losses and taking winners early is described as the reverse of the expected-value identity. Risk is to be defined before entry so one outcome stays bounded. Spreading names is cast as avoiding losses rather than meeting that bound.

A proposed resampling check

A follow-on Monte Carlo simulation is proposed to test whether outcomes differ systematically when holdings are not spread. The check compares an explicit rule, such as spreading versus concentrating holdings, over many paths instead of one historical anecdote.