Roth mandate and off calendar year plan

For an off calendar year plan with a 4/1-3/31 plan year, how will the Roth mandate work? For example the 2025 plan year ends 3/31/26, are all catch-ups made starting in January for HPI's treated as Roth?

In the catch-up rule published on September 16, a search on “limitation year” retrieves eight uses in three bits of text. These describe Treasury’s interpretations about how to coordinate § 401(a)(30), § 402(g), § 414(v), and § 415(c), with differences between or among the plan’s plan-accounting year, the limitation year, and a participant’s tax year.

https://www.govinfo.gov/content/pkg/FR-2025-09-16/pdf/2025-17865.pdf

Treas. Reg. §1.414(v)-2(d)(3)

Example (3).    Application of section 414(v)(7)(B) to a plan with a plan year other than the calendar year.

(i)         Facts. Participant B participates in an applicable employer plan sponsored by Employer E. The plan year begins on July 1 and ends on June 30. Participant B had $160,000 in wages within the meaning of section 3121(a) from Employer E for calendar year 2026, and is a catch-up eligible participant for calendar year 2027.  For the plan year beginning July 1, 2026, the plan allows all catch-up eligible participants to make catch-up contributions and requires that any elective deferrals in excess of an applicable limit made by catch-up eligible participants who are subject to the requirements of section 414(v)(7)(A) be designated Roth contributions.

 (ii)        Analysis. Because Participant B's FICA wages from Employer E for calendar year 2026 exceeded $155,000, Participant B is subject to the requirements of section 414(v)(7)(A) for 2027, and any catch-up contributions that Participant B makes under the plan during 2027 (which includes the second half of the plan year beginning July 1, 2026) must be designated Roth contributions. Because Participant B is permitted to make catch-up contributions that are designated Roth contributions under the plan for the plan year beginning July 1, 2026 (after Participant B reaches an applicable limit (as defined in § 1.414(v)-1(b)(1)), all catch-up eligible participants under the plan must be permitted to make catch-up contributions that are designated Roth contributions for the plan year. Furthermore, if the plan continues to permit catch-up contributions for the plan year beginning July 1, 2027, then any catch-up contributions that Participant B makes under the plan during the first half of that plan year must be designated Roth contributions (as well as any catch-up contributions in the second half of the plan year if Participant B had wages exceeding the applicable threshold in 2027).

Only authority I know of that is "directly" on point regarding your question.

I guess what I am wanting to know is, if a participant reaches his 402g limit on March 1, 2026 and the plan year for 2026 does not start until May 1, 2026, are any catch-ups made after March 1 but before May 1, 2026 subject to the Roth mandate? The reason I ask is because it is occuring before the first day of the plan year. But I think the law goes into effect 1/1/26 either way? ASsume high earner earned over $145,000 in calendar year 2025. THanks!

Parroting the Regulation example quoted above (changes to Reg language are bracketed and italicized), using your facts:

"Because Participant['s] FICA wages from Employer[] for calendar year 202[5] exceeded [$145,000], Participant[] is subject to the requirements of section 414(v)(7)(A) for 202[6], and any catch-up contributions that Participant[] makes under the plan during 202[6] (which includes the [latter portion] of the plan year beginning [May 1, 2025]) must be designated Roth contributions."

So, if your participant has catch up contributions in 2026, which you are saying they will (assuming they contribute to the plan after March 1, 2026)....

Just substituting your facts in the language from the example in the Regulation.

Great thank you!