Which term refers to rights to payment not classified specifically as accounts or chattel paper?

The term that accurately refers to rights to payment not specifically classified as accounts or chattel paper is "General intangibles." This category is defined under the Uniform Commercial Code (UCC) as any personal property that does not fall into other defined categories such as accounts or chattel paper. General intangibles encompass a wide range of rights, including things like intellectual property rights, certain contractual rights, goodwill, and other types of value that cannot be easily quantified or categorized.

Understanding general intangibles is critical in secured transactions because they represent significant sources of value for a debtor that can be pledged as collateral for loans. In contrast, the other terms listed relate to more specific types of property or rights and do not encompass this broader category. For instance, chattel property specifically pertains to tangible personal property, investment interests are typically associated with financial assets or equity, and secured collateral refers generally to any asset that secures a loan rather than a specific category of intangible rights. Therefore, "General intangibles" is the most appropriate and comprehensive choice for this question.