USA Stepped Up Valuation of AB Trust Assets

[Ultima]

One can use the current market value of assets passed to beneficiaries through an estate but not if the assets are passed via a trust. However, it seems to me that in the case of a disclaimer AB trust, the surviving spouse, provided he or she does not disclaim any oaf the decedent's assets, is left with a living trust containing all of the assets of the estate. A living trust is treated in the same way as if the assets were part of the estate. Accordingly, the assets in the survivor's living trust and be stepped in valuation rather than . What does the forum believe about this situation? Can all of the estate's assets be assigned a stepped up value when the survivor dies?