What is a glide path?

The logic runs from the balance sheet a household does not see: a salary is a claim on future cash flow, and for most careers that claim behaves like a bond, steady and hard to fire on short notice. Early in a career that claim is large relative to savings, so the investable portfolio can hold more equity risk without the household’s total risk rising as much as the number alone suggests.

The mix card on this site holds the split fixed rather than sliding it by age. The read behind that card is about how much the split itself is worth at a point in time; a glide path is the separate decision of how that split should change as the household’s own balance sheet changes.