(a)In general. Every taxpayer that has participated, as described in paragraph (c)(3) of this section, in a reportable transaction within the meaning of paragraph (b) of this section and who is required to file a tax return must file within the time prescribed in paragraph (e) of this section a disclosure statement in the form prescribed by paragraph (d) of this section. The fact that a transaction is a reportable transaction shall not affect the legal determination of whether the taxpayer's treatment