Corporate restructuring involves a range of activities to continually position a firm for shareholder value maximization, including portfolio restructuring, mergers and acquisitions, divestitures, financial engineering, and internal streamlining. Portfolio restructuring can involve mergers, asset or business acquisitions, divestitures through spin-offs or equity carveouts. Financial engineering alters a firm's debt-to-equity ratio through shares issues, debt issuance, buybacks, or foreign capital. Internal streamlining includes downsizing, cost reduction, and changes to structures, systems, and processes. Valuations are not objective but biased based on who pays for them, and simpler models generally perform better than complex ones.