Here's the question: Can a qualified retirement plan provide for accelerated vesting for all participants on a change in control, assuming the surviving entity continues to maintain the plan? For example, a 401(k)/(m) plan provides six-year graded vesting for matching contributions, but on a change in control, all participants become immediately fully vested. It doesn't seem to run against any of the minimum vesting requirements, but maybe there's a problem with the exclusive benefit rule? I just can't seem to find any discussion of such a vesting trigger in the context of qualified plans. I'm not that interested in corporate law/shareholder rights issues, just the ERISA and tax code qualified plan rules. Anyone have any insight on this point?

I don't see a problem. The only potential pitfall is extremely remote. That would be a claim of discrimination. But for the life of me I can't see that flying (although stranger claims have been made by IRS auditors in the past).

I agree, Mike, as to both your points: vesting trigger ok, and potential discrimination claim unlikely. I only see potential discrimination if most of the NHCEs are terminated as part of the merger/acquisition & the Plan's full vesting provision applies disproportianately to the HCEs--but, in that casse, it certainly would be a partial termination, and those terminated would become fully-vested just like the remaining HCEs.