The Shareholder-Director Exchange, or SDX, is a working group of independent directors and representatives from some of the largest and most influential long-term institutional investors. SDX participants came together to discuss shareholder-director engagement and to use their collective experience to develop the SDX Protocol, a set of guidelines to provide a framework for shareholder-director engagements.  According to SDX, the 10-point SDX Protocol offers guidance to public company boards and shareholders on when such engagement is appropriate, and how to make these engagements valuable and effective.

You can find a summary of the SDX Protocol here, and the full Protocol can be downloaded at the same web site.