§ 301.6212-2. Definition of last known address.

(i) A is an unmarried taxpayer. The address on A's 1999 Form 1040, U.S. Individual Income Tax Return, filed on April 14, 2000, and 2000 Form 1040 filed on April 13, 2001, is 1234 Anyplace Street, Anytown, USA 43210. On May 15, 2001, A informs the USPS of a new permanent address (9876 Newplace Street, Newtown, USA 12345) using the USPS Form 3575, “Official Mail Forwarding Change of Address Form.” The change of address is included in the weekly update of the USPS NCOA database. On May 29, 2001, A's address maintained in IRS records is changed to 9876 Newplace Street, Newtown, USA 12345.

(ii) In June 2001 the IRS determines a deficiency for A's 1999 tax year and prepares to issue a notice of deficiency. The IRS obtains A's address for the notice of deficiency from IRS records. On June 15, 2001, the Internal Revenue Service mails the notice of deficiency to A at 9876 Newplace Street, Newtown, USA 12345. For purposes of section 6212(b), the notice of deficiency mailed on June 15, 2001, is mailed to A's last known address.

(i) The facts are the same as in Example 1, except that instead of determining a deficiency for A's 1999 tax year in June 2001, the IRS determines a deficiency for A's 1999 tax year in May 2001.

(ii) On May 21, 2001, the IRS prepares a notice of deficiency for A and obtains A's address from IRS records. Because A did not inform the USPS of the change of address in sufficient time for the IRS to process and post the new address in Internal Revenue Service's records by May 21, 2001, the notice of deficiency is mailed to 1234 Anyplace Street, Anytown, USA 43210. For purposes of section 6212(b), the notice of deficiency mailed on May 21, 2001, is mailed to A's last known address.

(i) C and D are married taxpayers. The address on C and D's 2000 Form 1040, U.S. Individual Income Tax Return, filed on April 13, 2001, and 2001 Form 1040 filed on April 15, 2002, is 2468 Spring Street, Little City, USA 97531. On August 15, 2002, D informs the USPS of a new permanent address (8642 Peachtree Street, Big City, USA 13579) using the USPS Form 3575, “Official Mail Forwarding Change of Address Form.” The change of address is included in the weekly update of the USPS NCOA database. On August 29, 2002, D's address maintained in IRS records is changed to 8642 Peachtree Street, Big City, USA 13579.

(ii) In October 2002 the IRS determines a deficiency for C and D's 2000 tax year and prepares to issue a notice of deficiency. The Internal Revenue Service obtains C's address and D's address for the notice of deficiency from IRS records. On October 15, 2002, the IRS mails a copy of the notice of deficiency to C at 2468 Spring Street, Little City, USA 97531, and to D at 8642 Peachtree Street, Big City, USA 13579. For purposes of section 6212(b), the notices of deficiency mailed on October 15, 2002, are mailed to C and D's respective last known addresses.