Excess diversification and protected benefit

[Guest tmills]

Client currently allows excess diversification but would like to stop that and ony have the required diversification. I'm trying to determine if doing so would violate the protected benefit rules under 411(d)(6). Excess diversification is not an early retirement benefit, but arguably is an optional form. If excess is a protected benefit, it seems like the only cut back available would be for amounts accrued after the effective date of the change. That would be no fun to administer. Seems like another reason not to offer excess diversification. Thoughts are always appreciated.