Uniform Commercial Code (UCC): Primary framework governing payment instruments and fund transfers, particularly Articles 3 (Negotiable Instruments) and 4 (Bank Deposits and Collections). Essential for ensuring the authorization letter complies with standard commercial practices.

E-SIGN Act: Federal law validating electronic signatures and records. Crucial when the authorization letter needs to be executed electronically or stored in digital format.

State-Specific Authorization Laws: Various state-level requirements for authorization letters, including potential notarization requirements and specific power of attorney rules that vary by jurisdiction.

Bank Secrecy Act (BSA): Federal law requiring financial institutions to assist government agencies in detecting and preventing money laundering. Relevant for large transactions and proper documentation of payment authorizations.

Federal Tax Laws: IRS requirements governing payment documentation and related tax reporting obligations, ensuring proper tracking and reporting of authorized payments.

Privacy Laws: Including Gramm-Leach-Bliley Act and state-specific privacy regulations, governing the handling and protection of personal and financial information in authorization documents.