A credit shelter trust is created to preserve the decedent's estate tax exemption so a marital deduction would not apply in this case. Since the step-up in basis occured when this irrevocable trust was created in , when the exemption was just $,, the trust assets were not entitled to a second step-up at the death of the primary beneficiary in Apr 30, · Also, assets to this kind of trust receive what is called a stepped up basis. This means that when the beneficiary receives the trust assets, their basis is the fair market value on the day of. Aug 03, · Upon aunt’s death, the assets will be included in aunt’s taxable estate and receive a step-up in income tax basis (without a physical transfer of assets). The trust now has a ‘stepped-up’ tax basis and can sell the assets, if desirable, without triggering any taxable gain.