Although I do not believe it should or could be legally enforced, I still think M&A advisors on both the buy- and sell-side should adhere to a high ethical standard. Ideally, the sell-side advisors should make all relevant information on the target readily available for the buyer to assess. The data room should, therefore, allow for a fair assessment of potential DD risks within the company, which ought to minimize potential surprises for the buyer post-deal. As mentioned in a previous comment, it would be a good idea to have an M&A industry standard for ethics. Buy- and sell-side M&A advisors could thereby attain this certification, which, if widely recognized, would ensure potential clients that this particular advisor adheres to a high ethical standard.