Plan Year End

This may be a silly question but I have someone adamant that a 401(k) plan "has" to have a Plan Year from 1/1-12/31.  I tried to find it in the regulations, but can't seem to find it.  

Any help?

Thanks again everyone!

There are plenty of 401(k) plans with fiscal years ending on a date besides 12/31.  

Things like the 402(g) limit is a calendar year limit. 

I can think of a number of practical reason why a 1/1 to 12/31 year are easier but that is if the sponsor's corporate year is also those dates. But it isn't a requirement.

is this like the case Perry Mason lost?

technically the answer is YES, but only if you are referring to a SIMPLE 401k.

Thanks guys!  So a Simple 401k does have to be 1/1-12/31, but others can be off-calendar year.

Got it!

For future reference, whenever someone is "adamant", it might be useful to ask that person to provide his/her cite(s).

6 hours ago, Stash026 said:

This may be a silly question but I have someone adamant that a 401(k) plan "has" to have a Plan Year from 1/1-12/31.  I tried to find it in the regulations, but can't seem to find it.  

Any help?

Thanks again everyone!

Every one of our plans MATCHES the fiscal year of the sponsor; and when all those fiscal years changed to calendar years a number of years ago, we changed every plan to match. ADP makes every plan be calendar year (just one of the many things wrong with them) because that's all they know how to handle.  As to someone being adamant, YOU don't have to prove anything.  As someone else mentioned, my response to them is "please give me the cite that says that".  They can't; it doesn't exist.  And being "adamant" about something you don't know is the same as being an idiot and a bad advisor. Saying "I believe it's this way" is very different. Strong opinion to follow..... :-)