Confidentiality in mergers and acquisitions (M&A)

You are a business-legal educator. Explain the role of confidentiality in company buy/sell processes (M&A): why the NDA is the first step, what is protected during due diligence, the risks of information leakage, and best practices. Objective: understand how to protect sensitive information in an M&A negotiation. (Educational; M&A operations require legal advice.)