Automatic enrollment - protected benefit?

We have a 401k plan that started in 2023 and is large enough that it uses the automatic enrollment procedures.  Now this smaller company is considering purchasing a larger business that has their own 401k plan, that was created at least 20 years ago.

If the 2023 plan is merged into the larger plan, does the automatic enrollment feature have to carry over?  Is that considered a protected benefit?  

Or, if the smaller plan is terminated and the smaller plan's employees become eligible for the larger plan, and that larger plan does not have auto enroll?  Is that a problem?

Thank you

Another BenefitsLink discussion includes my inquiry about whether an automatic-contribution arrangement is a benefit, a burden, or neutral. https://benefitslink.com/boards/topic/73902-is-auto-enroll-an-actual-feature/

To consider whether either kind of election regime—affirmative or default—might be a protected benefit for a plan’s vesting provisions, one might consider that under either regime a participant retains a right to elect for or against deferrals.

This is not advice to anyone.

In terms of a protected benefit, consider that such cannot be cut back or eliminated with respect to benefits already accrued. That context really does not translate to automatic enrollment (which is a statutory design requirement) except that someone who is automatically enrolled must remain so unless they make an election. If the small plan of the buyer was merged into the larger plan of the acquired with that plan being the survivor, then that plan goes away for prospective benefits. I do not see anything as needing to be protected except possibly one's default enrollment. I would also consider a campaign to get affirmative elections (including zeros) from all employees previously in the buyer's plan so there are no residual default enrollments to worry about protecting if required.

Another consideration, institute auto enrollment for the merged plan as an enhancement.

I don't understand.  How is it a 411d6 protected benefit?  411d6 protects accrued benefits, early retirement benefits, and certain optional forms of benefit distributions.    AE is not a benefit within the meaning of 411d6.  It's just a feature of how contributions begin where employees can always choose to stop contributing or opt out.  (and frankly I don't see it as a BRF either).  my 2 cents... which are frankly not worth much anymore... if ever.

In sharing observations to help Santo Gold answer the question, it seems the three of us suggest reasonings under which an automatic-contribution arrangement would be neither a protected benefit (for ERISA title I and tax Code vesting provisions) nor a “benefit, right, or feature” (for I.R.C. § 401(a)(4) nondiscrimination).

I’m unaware of a Labor or Treasury rule, whether legislative or interpretative, that confirms that an automatic-contribution arrangement is not such a benefit.

(That’s not surprising considering that the agencies made relevant rules before automatic-contribution arrangements became much more common after the 2006 Act.)

This is not advice to anyone.

Consider CuseFan’s practical suggestions.