Two Ways to Count the Clock

Several apportionment methodologies rely on a time-rule fraction: how much of a grant's accrual period fell inside the marriage? The answer depends on how you count time. Some approaches — notably the original Nelson opinion — counted in whole months. Modern practice more often uses exact days.

The two charts above use the same grant, same DOS, same methods. Only the time-counting rule changes. On the left, the daily calculation divides days elapsed by total days — the curves are smooth. On the right, whole months elapsed divided by total months — the curves step at month boundaries and hold flat in between.

Does it matter?

At each vest date, both calculations agree. Between vests, the monthly version lags slightly because it only advances at each month boundary rather than continuously. The numerical difference at any given DOS is usually small — single digits of shares on a typical grant — but it can matter when:

• The DOS falls mid-month and precision matters for a settlement.
• Opposing counsel argues one method is more "correct" than the other.
• Large grants magnify fractional differences into real dollars.

Not every method is affected. Vested Shares, for example, is a binary check at vest time with no time-rule denominator — its curve looks the same either way. The distinction only applies to methods that use a time-rule fraction (such as the Nelson and Hug formulas), where it controls whether the denominator counts days or months.

Which to use

The main tool defaults to daily calculation because it produces smoother, more defensible curves and better reflects how time actually passes during a marriage. If a court or opposing counsel insists on whole-month computation, the Calc toggle in each analysis view lets you switch.