Uniform Commercial Code (UCC): Primary governing law for negotiable instruments (Article 3) and secured transactions (Article 9) if the note is secured. Essential for determining negotiability and enforcement of the promissory note.

State-Specific Laws: Individual state regulations governing promissory notes, including state-specific interest rate limits (usury laws) and statute of limitations for enforcement of the note.

Truth in Lending Act (TILA): Federal law requiring specific disclosures for consumer credit transactions, including disclosure of key terms and conditions of the lending arrangement.

Federal Reserve Regulations: Particularly Regulation Z, which implements the Truth in Lending Act and applies to consumer credit transactions, requiring specific disclosures and practices.

Securities Laws: Federal and state securities regulations, including the Securities Act of 1933, which may apply if the note is considered a security under relevant definitions.

Tax Considerations: Internal Revenue Code provisions and state tax regulations regarding the treatment of interest income and other tax implications of the promissory note.

Bankruptcy Code: Federal bankruptcy laws affecting the enforceability of the note in case of bankruptcy proceedings by either party.

State Contract Law: Basic contract formation requirements including consideration, capacity to contract, and other state-specific contractual obligations and rights.