How does a shareholder agreement, also commonly referred to as a buy-sell agreement, work? The shareholders of a bank holding company (“BHC”) sign an agreement that restricts how the shares of the holding company can be sold or otherwise transferred. The agreement explains what happens to the stock in the event of death, disability, bankruptcy, and divorce of the shareholders. If employees own stock, the agreement should require the sale of their stock back to the company upon termination of employment.