Example. The Federal tax liability secured by a lien is $1,000. The fair market value of all property which after the discharge will continue to be subject to the Federal tax lien is $10,000. There is a prior mortgage on the property of $5,000, including interest, and the property is subject to a prior lien of $100 for real estate taxes. Accordingly, the taxpayer's equity in the property over and above the amount of the mortgage and real estate taxes is $4,900, or nearly five times the amount required to pay the assessed tax on which the Federal tax lien is based. Nevertheless, a discharge under this subparagraph is not permissible. In the illustration, the sum of the amount of the Federal tax liability ($1,000) and of the amount of the prior mortgage and the lien for real estate taxes ($5,000 + $100 = $5,100) is $6,100. Double this sum is $12,200, but the fair market value of the remaining property is only $10,000. Hence, a discharge of the property is not permissible under this subparagraph, since the Code requires that the fair market value of the remaining property be at least double the sum of two amounts, one amount being the outstanding Federal tax liability and the other amount being all prior liens upon such property. In order that the discharge may be issued, it would be necessary that the remaining property be worth not less than $12,200.
and if the period of limitation on collection after assessment of the tax liability has not expired, the appropriate official may revoke the certificate and reinstate the tax lien. The provisions of this subparagraph do not apply in the case of the lien imposed by section 6324 relating to estate and gift taxes.
Example. On March 1, 1967, an assessment of an unpaid Federal tax liability is made against A. On March 1, 1968, notice of the Federal tax lien, which arose at the time of assessment, is filed. On April 1, 1968, A executes a bona fide mortgage on property belonging to him to B. On May 1, 1968, a certificate of release of the tax lien is erroneously issued and is filed by A in the same office in which the notice of lien was filed. On June 3, 1968, the lien is reinstated in accordance with the provisions of this subparagraph. On July 1, 1968, A executes a bona fide mortgage on property belonging to him to C. On August 1, 1968, a notice of the lien which was reinstated is properly filed in accordance with the provisions of § 301.6323(f)-1 . The mortgages of both B and C will have priority over the rights of the United States with respect to the tax liability in question. Because a reinstated lien continues in existence only until the expiration of the period of limitation on collection after assessment of the tax liability to which the lien relates, in the absence of any extension or suspension of the period of limitation on collection after assessment, the reinstated lien will become unenforceable by reason of lapse of time after February 28, 1973.
26 C.F.R. §301.6325-1
Secs. 6324B (90 Stat. 1861, 26 U.S.C. 6324B ) and 7805 (68A Stat. 917, 26 U.S.C. 7805 )