tax liability
(C) Tax liability. A tax liability means the liability for any tax imposed by title 26 of the United States Code (including any interest, additional amount, addition to the tax, or penalty) and does not include the liability for any tax imposed by any other jurisdiction nor any liability imposed by other Federal statutes. (D) Such taxpayer. A contact is with respect to the determination or collection of the tax liability of such taxpayer when made while determining or collecting the tax liability of a particular, identified taxpayer. Contacts made during an investigation of a particular, identified taxpayer are third-party contacts only as to the particular, identified taxpayer under investigation and not as to any other taxpayer whose tax liabilities might be affected by such contacts. (ii) Examples. The following examples illustrate the operation of this paragraph (c)(3): (4) Discloses the identity of the taxpayer being investigated(i) Explanation. An IRS employee discloses the taxpayer's identity whenever the employee knows or should know that the person being contacted can readily ascertain the taxpayer's identity from the information given by the employee. (ii) Examples. The following examples illustrate this paragraph (c)(4): (5) Discloses the association of the IRS employee with the IRS. An IRS employee discloses his association with the IRS whenever the employee knows or should know that the person being contacted can readily ascertain the association from the information given by the employee.