Miss. Code § 91-7-159
The executor, trustee, or other fiduciary having discretionary powers under a last will and testament or transfer in trust shall be authorized to enter into agreements with the commissioner of internal revenue of the United States of America and other taxing authorities to exercise the fiduciary's discretion so that the assets to be distributed in satisfaction of a bequest or transfer in trust will be selected in such a manner that cash and other properties distributed will have an aggregate fair market value representative of the pecuniary legatee's or transferee's proportionate share of the appreciation or depreciation in value to the date, or dates, of distribution of all property then available for distribution in satisfaction of such bequest or transfer. It is the purpose of this section to authorize such fiduciary to enter into any agreement that may be necessary or advisable in order to secure for federal estate tax purposes the maximum marital deduction available under the Internal Revenue Laws of the United States of America, and to do and perform all acts incident to such purpose.
Miss. Code § 91-7-159