The headline number
On the standard sample grant (480 shares vesting quarterly over four years from 2020-01-01), shifting the date of separation by just 6 months — from 2022-07-01 to 2023-01-01 — changes how many shares the community owns by 13–60 shares, depending on which apportionment method is used.
That's not a rounding error. It's the entire reason "date of separation" gets litigated in equity-heavy cases. The math is mechanical, but the inputs aren't — and a few months' difference in the input compounds across every tranche.
The numbers, method by method
The community-property share count under each method at the two candidate DOSes. Both runs use the same grant, the same marriage date (2019-06-01, before the grant), and the same hire date (2017-01-01).
| Method | DOS = 2022-07-01 | DOS = 2023-01-01 | Shift |
|---|---|---|---|
| Vested Shares | 300 | 360 | +60 |
| Ratable Vested | 300 | 360 | +60 |
| Vest-Level Nelson | 435 | 460 | +25 |
| Grant-Level Nelson | 300 | 360 | +60 |
| Vest-Level Hug | 217 | 230 | +13 |
| Grant-Level Hug | 211 | 246 | +35 |
| (of 480 total shares) | |||
Why the methods diverge
Three of the six methods (Vested Shares, Ratable Vested, and Grant-Level Nelson) move identically when DOS shifts by a clean tranche boundary — every share that vested between the two DOSes counts as community under all three, and nothing else changes. On this grant, six months captures two full quarterly tranches of 30 shares each, which is exactly the shift shown.
Vest-Level Nelson moves less because it already counted partial credit for the unvested tranches at the earlier DOS. Pushing DOS forward turns those partial fractions into full ones, but the incremental gain is smaller than under the methods that count tranches as all-or-nothing.
The two Hug methods anchor their denominator to the hire date rather than the grant date — three extra years of "pre-grant marriage time" in the denominator. That dilutes the impact of any DOS shift. Hug-based methods are structurally less sensitive to DOS than Nelson-based ones, which is part of why the choice between Nelson and Hug is its own settlement variable, not just a characterization question.
What this means in practice
If your case is contested on the date of separation, the methodology you've stipulated to (or are arguing for) determines how much that DOS fight is worth in dollars. Two scenarios worth running the numbers on:
- You want the later DOS and the methodology is Nelson-based: the DOS shift moves the maximum number of shares in your direction. Worth fighting for.
- You want the later DOS but the methodology is Hug-based: the same DOS fight buys you less because Hug's longer denominator already absorbed most of the marital time. A negotiation over methodology may move more than a fight over a few months of DOS.
The reverse is also true: if you're arguing for the earlier DOS, the same logic applies in the other direction. Either way, the right comparison isn't "what's the right separation date"; it's "what does each candidate date cost or save me under each plausible method." That's the math the tool runs at the top of this page.