The current issue with adding carrying charges to the cost basis, pursuant to Treas. Reg. §1.266-1(b)(1), is the charges must be "expressly deductible under the provisions of Subtitle A of the Code".
Although there has generally been silence on this subject, after tax reform (the TCJA), miscellaneous itemized deductions are no longer deductible and, as such, should not (logically) fall within the carrying charges that can be added to the cost basis (i.e., chargeable to capital account).
