Uniform Commercial Code (UCC): Primary source of commercial law in the US, particularly Article 2 (Sale of Goods) and Article 9 (Secured Transactions). Essential for transactions involving personal property.

State-Specific Contract Laws: Individual state contract laws, including Statute of Frauds requirements and state-specific consumer protection regulations that vary by jurisdiction.

Federal Trade Laws: Including Federal Trade Commission Act and Magnuson-Moss Warranty Act for consumer warranties, and Consumer Product Safety Act where applicable.

Property Laws: State property laws, local zoning regulations, and Real Estate Settlement Procedures Act (RESPA) if real estate is involved in the transaction.

Tax Regulations: Internal Revenue Code, state and local tax regulations, and sales tax requirements applicable to the transaction.

Environmental Regulations: EPA regulations, state environmental laws, and local environmental ordinances that may affect the sale transaction.

Securities Laws: Securities Act of 1933 and Securities Exchange Act of 1934, if the transaction involves securities or related financial instruments.

Antitrust Laws: Sherman Antitrust Act, Clayton Act, and Federal Trade Commission Act provisions relating to competition and fair trade practices.

Industry-Specific Regulations: Specific regulations and requirements that apply to particular industries or types of goods/services being sold.

International Trade Laws: Convention on Contracts for the International Sale of Goods (CISG) and import/export regulations if the transaction has international elements.