Thanks to a tip from @ZedtheGamer, I encountered the concept of anniversary month in this bit of convolution:
Anniversary month evidently means the month in which the anniversary of a given event occurs. Here’s how it’s defined in an Illinois statute:
“Anniversary month” means the month in which the anniversary of the limited liability company occurs.
By default it’s forward-looking, but here’s an example where it’s backward-looking, although that’s inconsistent with how anniversary is used generally:
“Anniversary Month” means, with respect to any date of determination, the calendar month of the prior calendar year corresponding to the calendar month in which such date of determination occurs.
And anniversary month is also used to mean the month of a subsequent year corresponding to a month (not the month in which a day occurs) of a given year. (For an example of that use, see the last of the examples below.)
The meaning of anniversary month isn’t that complicated, but I recommend you not use it. If I’ve lived to 59 years of age without ever having encountered anniversary month, that suggests it’s not standard. And the economy afforded by anniversary month is modest. So I say the heck with it.
Below are some EDGAR examples featuring anniversary month. In each, anniversary month isn’t used as a defined term. That simplifies matters, but is also ensures that readers will likely spin their wheels just a bit when they encounter anniversary month. In each example, the text featuring anniversary month is in italics and in brackets, and it’s followed by my preferred alternative text, also in italics and in brackets.
The annual Application Service Provider fee shall be payable on the Effective Date and annually during [each anniversary month thereafter] [the month in which the anniversary of the Effective Date occurs].
The first installment shall be paid in accordance with Section 8; thereafter, installment payments shall be paid [in the anniversary month of the date of Termination of Employment] [annually in the month during which the anniversary of the date of Termination of Employment occurs].
The Company will retain the right to repurchase these shares at $0.01 per share purchase price should the Executive experience a termination of employment, as such term is used in the Stock Plan, but this repurchase right will lapse as to one quarter of the total number of shares on the last calendar day of the [anniversary month of hire] [month during which the anniversary of the Executive’s date of hire occurs] each year the executive is employed until fully vested, and shall be subject to the other terms and conditions specified in a separate grant agreement; and
Rent payable pursuant to Section 4.1 above will be adjusted on each anniversary of the Effective Date by a fraction whose numerator is the Price Index published for the then most recent [anniversary month of] [month of that year corresponding to] the first month of the Term and whose denominator is the Base Price Index.
Hasta la vista, anniversary month.
A few comments, mostly off topic:
1/ The first example in which you give your recommended alternative seems to create a perpetual obligation rather than a conditional one. To avert that outcome, perhaps something like this: ‘To become an Application Service Provider for a year, each ASP shall pay the fee on the Effective Date. To remain an ASP, each ASP must pay the then-applicable fee during the month in which the anniversary of the Effective Date occurs.’ I’m uneasy about that ‘must’.
2/ The third example sins in an off-topic way: it uses a period (of time) as the ending of a larger period: ‘the right will lapse on the last calendar day’, creating unclarity (exactly when on the last calendar day will the right lapse?). Better: ‘will lapse at the end of the last calendar day’, etc.
3/ The fourth EDGAR example has the same flaw: ‘on each anniversary of the Effective Date’. Is each ‘anniversary’ a point or a period? If a point, what point? Initial midnight? Noon? ‘Close of business’? Final midnight? If a day, when on that day does the rent adjust?
Lesson 1: getting rid of ‘anniversary month’ but keeping ‘anniversary’ requires making clear whether ‘anniversary’ is a period or a point.
Lesson 2: Always define two-ended periods from point to point (and a one-ended period from its startpoint or endpoint, whichever it has).
4/ If the case against ‘anniversary month’ is that (a) it’s only a little conciser than some alternatives and (b) it’s not ‘standard’, I want to know what you’ve done with Ken Adams. He always said ‘standard’ contract language is dysfunctional!
5/ I groan at things like ‘eight-month anniversary’. Has the use of ‘anniversary’ for periods other than years crept into contracts? –Wright