Under the new proposed regs, who has the onus for sending a 70.5 distribution notice to a terminated participant from a non-Title I 403(B) arrangement.

It would appear that under the new regs, the plan sponsor is off the hook at termination of employment and that the custodian of a rollover IRA has such responsiblities.

However, assume for this argument that the new notice was provided at termination by the plan sponsor, but the participant leaves the 403(B) account intact and does not roll it into an IRA.

Does the account custodian have to onus to remind the terminated participant of his/her obligation to distribute from the 403(B) account at 70.5?

OR

Does the onus fall on the plan sponsor, since the account is still a "plan asset" as it never was removed and is technically, still part of the plan?

I didn't know that 403(B) plans have plan assets since participant's interest in plan are not held in trust like qualified plans. I thought he burden of filing the distirbution notice was on the custodian holding the assets since a 403(B) plan is treated as an IRA under the minimum distribution regs.