Determining the mean acquisition cost of individual equity units involves dividing the total expenditure on a specific stock by the number of units acquired. For instance, if an investor purchased 100 shares at $10 each and later acquired an additional 50 shares at $12 each, the total investment is (100 $10) + (50 $12) = $1600. Dividing this total investment by the total number of shares (150) yields an individual unit cost of $10.67 (rounded to the nearest cent).
Establishing this per-unit cost is crucial for assessing investment performance, particularly when evaluating capital gains or losses upon the disposal of equity. Furthermore, it aids in informed decision-making regarding future acquisitions or dispositions of the same equity, facilitating strategic portfolio management. This type of calculation has been a foundational element of investment analysis since the formalization of modern portfolio theory.