Q:

Can an employer make a 401k vesting schedule worse?

Say a person works for an employer for 2+ years based on the statement (promise?) that they will be 100% vested in their 401k employer match after 5 years. Is the employer then permitted to change the rules so that it will take the employee 6 years to be fully vested?
From my research it seems they may be allowed to do this provided they don't reduce the percentage already vested at any point? However even given that, it would still seem unfair since the job would have been partly been accepted based on the original promise, and when the vesting schedule is made worse, then at the point it's made worse, it's like telling someone, hey that money you have been anticipating (and working under the assumption) to be fully yours by year 5 will now take until year 6 to be fully yours.
EDIT: I just found the following guidance on the IRS website
https://www.irs.gov/retirement-plans/change-in-plan-vesting-schedules
Seems from this link (esp. the example they offer) that there are actually quite tight restrictions on what employers can do... e.g. seems to me that if accrued non-vested amounts are additionally restricted by a worsened future vesting schedule, that this may not be allowed after all? And even for people with less than 3 years service?!

A:

My interpretation of the IRS link you provided is that any amount of existing employer contributions must follow the least restrictive of the old and new vesting schedules, AND, any participating employee who has been an employee for at least 3 years can elect to stay on the old plan if the wish (for both existing and future contributions). Perhaps this could be best explained with an example:
Old Vesting Schedule:

1 year = 20%
2 years = 40%
3 years = 60%
4 years = 80%
5 years = 100%

New Vesting Schedule:

2 year = 20%
3 years = 40%
4 years = 60%
5 years = 80%
6 years = 100%

You mentioned you have 2 years, so for this example you currently would be vested at 40%. Had you had 3 years you could elect to completely stay on the old plan and all of your existing and future contributions would be fully vested after 5 years. But with less than 2 years it works like this:

All employer contributions that you have at the time of the plan change will continue to vest on the old schedule (completely vested after 5 years- up to 3 years from now).
All future employer contributions that you receive will vest on the new schedule (completely vested after 6 years - up to 4 years now.) Contributions you receive "today" would be vested at 20%, whereas those that were made "before" were vested at 40%.

It may be easier to conceptualize this as your account "splitting" into two separate accounts on the day of the plan change, with all new contributions going into the second account and each account vesting at its respective schedule.

