26 CFR §20.2053-8

1. (a)Expenses incurred in administering property included in a decedent's gross estate but not subject to claims fall within the second category of deductions set forth in § 20.2053-1, and may be allowed as deductions if they—
   1. (1)Would be allowed as deductions in the first category if the property being administered were subject to claims; and
   2. (2)Were paid before the expiration of the period of limitation for assessment provided in section 6501.
2. (b)These expenses may be allowed as deductions only to the extent that they would be allowed as deductions under the first category if the property were subject to claims. See § 20.2053-3. The only expenses in administering property not subject to claims which are allowed as deductions are those occasioned by the decedent's death and incurred in settling the decedent's interest in the property or vesting good title to the property in the beneficiaries. Expenses not coming within the description in the preceding sentence but incurred on behalf of the transferees are not deductible.
3. (c)The principles set forth in paragraphs (b), (c), and (d) of § 20.2053-3 (relating to the allowance of executor's commissions, attorney's fees, and miscellaneous administration expenses of the first category) are applied in determining the extent to which trustee's commissions, attorney's and accountant's fees, and miscellaneous administration expenses are allowed in connection with the administration of property not subject to claims.
4. (d)The application of this section may be illustrated by the following examples: