What are the potential consequences to the sponsor of a 457(B) plan that has not yet put plan assets in trust, as required by 457(g)?

The plan sponsor is probably at risk of the plan being declared an (f) plan, which would probably mean that all assets would be immediately taxable to participants in the tax year the plan problem is discovered. The unpleasantness that follows this type of problem is not something I would like to be near. The IRS issued a TAM last year relative to a "bad" 457, while not totally on point, will give you the IRS position. Look on Carol's site for the TAM.

We are in process of cleaning up several plans of this nature, before discovery and there may be some opportunities here for "creative planning".