Denial of deduction in certain cases

(A) In general No deduction shall be allowed for a contribution of an undivided portion of a taxpayer’s entire interest in tangible personal property unless all interests in the property are held immediately before such contribution by— (i) the taxpayer, or (ii) the taxpayer and the donee.

(B) Exceptions The Secretary may, by regulation, provide for exceptions to subparagraph (A) in cases where all persons who hold an interest in the property make proportional contributions of an undivided portion of the entire interest held by such persons.