Internal Revenue Code (IRC): Federal tax regulations governing the treatment of employee reimbursements, including distinctions between taxable and non-taxable reimbursements

IRS Publication 463: Specific guidance on travel, gift, and car expenses reimbursements, including documentation requirements and tax implications

Fair Labor Standards Act (FLSA): Federal labor law that may impact how certain reimbursements are handled, especially in relation to minimum wage and overtime calculations

State Labor Laws: Various state-specific regulations governing employee reimbursements, which may provide additional requirements beyond federal law

Accountable Plan Rules: IRS rules under IRC ยง62(c) defining requirements for tax-free reimbursements, including business connection, substantiation, and return of excess amounts

State Labor Codes: Specific state requirements for expense reimbursements, such as California Labor Code Section 2802 mandating employer reimbursement of necessary business expenses

IRS Documentation Requirements: Specific record-keeping requirements for expense documentation, including receipts, timing, and substantiation rules

ERISA: Employee Retirement Income Security Act considerations if reimbursements interact with benefit plans or compensation structures

Privacy Laws: Federal and state privacy regulations that may apply when handling employee personal information in reimbursement documentation

Corporate Policy Compliance: Internal company policies and procedures that must be reflected in the reimbursement letter to maintain consistency with established protocols