Trade date vs Settlement date

I'm prepare a Schedule H (Form 5500) for a 2017 calendar year 401(k) plan. The plan merged with another plan effective on 1/1/18. The majority of mutual funds were liquidated around 1/28/17 which was the trade date reported by the financial institution & received by the other plan on 1/2/18 which would be the settlement date. How should these transferred plan assets be reported on the 2017 Schedule H?

I think you mean that the mutual funds were liquidated on 12/28/17.

Were the funds received immediately processed to be transferred to the receiving trust?  Or were the funds held until 1/2/18 and then transferred to the receiving trust?

IMHO, if the funds were immediately processed for transfer on 12/28/17, then you would use that date, with the receiving trust showing a receivable as of the 12/28/17 date.  If the funds were not transferred until 1/2/18, then you have a one day 5500 filing for the original plan.

Always good to have the transaction begun and completed in the same plan year.

The sending financial institution lists the funds as "Funds in Transfer" as of 12/31/17. The receiving institution books the funds as of 1/2/18. Therefore, it appears, these funds should be listed on the Form 5500 as plan assets as of 12/31/17?