Thanks to regulations, 403(b) plans are becoming more and more like 401(k) plans. It’s to the point were many advisors and third-party administrators get the idea they can merge or convert the plans, especially trying to morph a 403(b) into a 401(k) plan, but they can’t.
A 403(b) plan of a 501(c)(3) tax-exempt organization can’t be merged with a 401(k) plan; the only exception involves churches, which, subject to certain restrictions, were permitted to merge 401(k) and 403(b) plans that they sponsor.
The only way to move 403(b)money into a 401(k) plan is a plan termination where participants would elect the right to rollover their plan assets to a new 401(k) plan or an IRA. Until we get legislation that will allow a merger, we will still have this workaround.