Can an executor place a missing beneficiary's share in a holdback account instead of waiting indefinitely to distribute?

Yes - holding back a missing beneficiary's specific share while distributing the rest of the estate to everyone else is a common and practical approach, rather than leaving the entire estate open indefinitely because one person can't be found. The held-back funds are typically kept in a separate account, sometimes with the estate's lawyer, sometimes through the court, until the missing person is found, a court authorizes another resolution, or another protective step like indemnity insurance is put in place.

A holdback doesn't eliminate the trustee's other obligations - a genuine search for the missing beneficiary should still continue, and the trustee should keep records of what's being held, why, and what ongoing efforts are being made to locate the person. Simply parking the money and stopping the search isn't the same as properly managing a holdback.

How long a holdback should realistically continue, and when it's appropriate to ask a court for direction on what to do with funds that remain unclaimed, depends on the size of the share and the facts of the search - there's no standard duration that applies to every estate. Legal advice helps set reasonable expectations and next steps for both the trustee and the other beneficiaries waiting on final distribution.