See paragraphs (a) and (e) of § 301.6323(h)-1 for definitions of the terms "security interest" and "tax lien filing," respectively. For purposes of this section, a judgment lien is a lien held by a judgment lien creditor as defined in paragraph (g) of § 301.6323(h)-1 .
Such an agreement qualifies as a commercial transactions financing agreement only with respect to loans or purchases made under the agreement before (i) the 46th day after the date of tax lien filing or, (ii) the time when the lender or purchaser has actual notice or knowledge (as defined in paragraph (a) of § 301.6323(i)-1 ) of the tax lien filing, if earlier. For purposes of this paragraph, a loan or purchase is considered to have been made in the course of the lender's or purchaser's trade or business if such person is in the business of financing commercial transactions (such as a bank or commercial factor) of if the agreement is incidental to the conduct of such person's trade or business. For example, if a manufacturer finances the accounts receivable of one of his customers, he is considered to engage in such financing in the course of his trade or business. The extent of the priority of the lender or purchaser over the tax lien is the amount of his disbursements made before the 46th day after the date the notice of tax lien is filed, or made before the day (before such 46th day) on which the lender or purchaser has actual notice or knowledge of the filing of the notice of the tax lien.
For purposes of this subparagraph, the term "paper of a kind ordinarily arising in commercial transactions" in general includes any written document customarily used in commercial transactions. For example, such written documents include paper giving contract rights (as defined in subparagraph (2) of this paragraph (c)), chattel paper, documents of title to personal property, and negotiable instruments or securities. The term "commercial financing security" does not include general intangibles such as patents or copyrights. A mortgage on real estate (including a deed of trust, contract for sale, and similar instrument) may be commercial financing security if the taxpayer has an interest in the mortgage as a mortgagee or assignee. The term "commercial financing security" does not include a mortgage where the taxpayer is the mortgagor or realty owned by him. For purposes of this subparagraph, the term "inventory" includes raw materials and goods in process as well as property held by the taxpayer primarily for sale to customers in the ordinary course of his trade or business.
26 C.F.R. §301.6323(c)-1