External threats are anything from your organization's outside environment that can adversely affect its performance or achievement of its goals. Ironically, stronger organizations can be exposed to a greater level of threats than weaker organizations, because success breeds envy and competition to take what your organization has achieved.
Examples of external threats include new and existing regulations, new and existing competitors, new technologies that may make your products or services obsolete, unstable political and legal systems in foreign markets and economic downturns. Sometimes you can turn a threat into an opportunity, such as a new technology that may displace one of your key products but also provides an opportunity for new product development.