Who can be the beneficiary of a beneficiary?

A 401k participant passed away leaving his wife as his 401k account beneficiary.  The account has stayed in the plan and has been re-titled to be in her name at this time.

Are there are restrictions on who she can name as her beneficiary for this account?  She has no kids and does not want to leave it to her brothers.  Can she name a non-profit or other entity?

Thank you

The plan’s administrator ought to Read The Fabulous Document.

First, a plan might not provide for a beneficiary to name a further beneficiary. A plan might provide that only a participant may name a beneficiary.

On a participant’s beneficiary’s death (even if after the participant’s death), a plan might provide that a remaining benefit goes to the contingent beneficiaries the participant named, if any then is living or in existence, and otherwise to a default the plan specifies in relation to the participant.

IF a beneficiary may name a further beneficiary, it’s unusual for a plan to restrict the kinds of persons who or that one may name as a beneficiary.

In my experience, some participants name a charity for some or all of a participant’s death benefit. (I have no experience with an employment-based plan that allows a beneficiary to name a further beneficiary.)

To avoid any potential limitations imposed by the plan she could take a distribution and rollover to an IRA where she then has complete control over where it goes upon her death.

IF the plan contains restrictions such as those mentioned by @Peter Gulia, and IF the plan does not want those restrictions, then the plan sponsor should consider amending the plan document, sooner rather than later.