A company is owned by its shareholders. The shareholders appoint the directors who then appoint the management. The directors are the “soul” and conscience of the company. They are liable for its actions. Shareholders are not liable for company actions. Management may or may not be liable for company actions. Often these roles are assumed by the same individuals but as a company grows and becomes larger, this may not be the case. When a company is created, its founding shareholders determine how a company will be owned and managed. This takes the form of a “shareholders agreement”.
As new shareholders enter the picture, for example angel investors, they will want to become part of the agreement and they will most likely add additional complexity. For example, they may want to impose vesting terms and also mechanisms to ensure that they ultimately can exit and get a return on their investment. Not having such an agreement can lead to serious problems and disputes and can result in corporate failure. It’s a bit like a prenuptial agreement.
http://www.sfu.ca/~mvolker/biz/agree.htm
