Lesson 4 of 25 · 7 min

Holding periods, and why the calendar is part of the rule

One day can move a figure between two categories, and the rule does not ask why the sale happened when it did.

Many systems sort a gain into categories by how long the asset was held, and the sorting is done by a date rather than by any judgement about what the holder intended.

The structure is the same even where the details differ. A clock starts at acquisition, a boundary sits somewhere along it, and the gain is characterised by which side of the boundary the disposal falls on. Systems differ on where the boundary sits, on whether it is counted in months or days, on whether the clock starts at the trade or at settlement, and on whether the first day counts. Those are not details. They are the rule.

The consequence is discontinuity. A continuous variable — days held — produces a step change in outcome. Suppose a holding is acquired on 17 March and disposed of on 14 March the following year, which is 362 days. Assume, only so the example has an edge to fall off, a boundary of more than 365 days. The gain of $86,400 lands on the near side. At two assumed characterisations of 32 percent and 17 percent, the figures are $27,648 and $14,688, a gap of $12,960 opened by three days.

Both of those percentages are assumptions of the example and nothing more; no system is being described and no rate is being stated. The point survives whatever numbers are used, because the point is the shape. A threshold is not a slope: the variable moved by less than one percent of the period and the result moved by 88 percent.

Lesson 15 shows that the clock can also be stopped or sent back to zero by events that have nothing to do with the calendar. Where the boundary sits for a particular holder, and whether their system draws the distinction at all, belongs with their own adviser.

Key terms

Holding period: The elapsed time between acquiring an asset and disposing of it, measured by whatever convention the governing rules specify.
Boundary: The point along that clock at which the characterisation of a gain changes. It is a date test, not a test of motive.
Discontinuity: A result that jumps rather than slides. One more day of holding can change an outcome by far more than one day of value.

Worked example

Three days, one boundary

A holding acquired on 17 March and disposed of on 14 March the following year, producing a gain of $86,400. The boundary and both percentages below are assumptions of the example.

Days held: 362
Assumed boundary in this example: More than 365 days
Gain: $86,400
At an assumed 32 percent: $27,648
At an assumed 17 percent: $14,688
Difference: $12,960

The input moved by three days out of 365. The output moved by $12,960. That asymmetry is what a threshold does.

Check yourself

Under an assumed boundary of more than 365 days, a disposal on day 362 produces a gain of $86,400. Two assumed characterisations of 32 percent and 17 percent give $27,648 and $14,688. What does the example show about how the rule is built?

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Educational only. Nothing in this lesson is investment, legal or tax advice, or a recommendation to enter into any transaction. Figures are illustrative and computed from the inputs stated in the lesson.