26 C.F.R. § 301.6323(d)-1
For purposes of subparagraph (1) of this paragraph (a), a contract right (as defined in paragraph (c)(2)(i) of § 301.6323(c)-1 ) is subject, at the time of tax lien filing, to the lien imposed by section 6321 if the contract has been made by such time. An account receivable (as defined in paragraph (c)(2)(ii) of § 301.6323(c)-1 ) is subject, at the time of tax lien filing, to the lien imposed by section 6321 if, and to the extent, a right to payment has been earned by performance at such time. For purposes of subparagraph (2) of this paragraph (a), a judgment lien is a lien held by a judgment lien creditor as defined in paragraph (g) of § 301.6323(h)-1 . For purposes of this section, it is immaterial that the written agreement provides that the disbursements are to be made at the option of the person making the disbursements. See paragraphs (a) and (e) of § 301.6323(h)-1 for definitions of the terms "security interest" and "tax lien filing," respectively. See paragraph (a) of § 301.6323(i)-1 for certain circumstances under which a person is deemed to have actual notice or knowledge of a fact.
Example 1. On December 1, 1967, an assessment is made against A with respect to his delinquent tax liability. On January 2, 1968, A enters into a written agreement with B whereby B agrees to lend A $10,000 in return for a security interest in certain property owned by A. On January 10, 1968, in accordance with § 301.6323(f)-1 notice of the tax lien affecting the property is filed. On February 1, 1968, B, without actual notice or knowledge of the tax lien filing, disburses the loan to A. Under local law, the security interest arising by reason of the disbursement is entitled to priority over a judgment lien arising January 10, 1968 (the date of tax lien filing) out of an unsecured obligation. Because the disbursement was made before the 46th day after tax lien filing, because the disbursement was made pursuant to a written agreement entered into before tax lien filing, and because the resulting security interest is protected under local law against a judgment lien arising as of the date of tax lien filing out of an unsecured obligation, B's $10,000 security interest has priority over the tax lien.
Example 2. Assume the same facts as in example 1 except that when B disburses the $10,000 to A on February 10, 1968, B has actual knowledge of the tax lien filing. Because the disbursement was made with actual knowledge of tax lien filing, B's security interest does not have priority over the tax lien even though the disbursement was made before the 46th day after the tax lien filing. Furthermore, B is not protected under § 301.6323(a)-1(a) as a holder of a security interest because he had not parted with money or money's worth prior to the time the notice of tax lien was filed (January 10, 1968) even though he had made a firm commitment to A before that time.
26 C.F.R. §301.6323(d)-1