SEC

SEC is an acronym which may refer to

Securities and Exchange Commission, financial regulatory agencies in several different countries

Wikinews currently has a category for the US Securities and Exchange Commission only

Solar Entertainment Corporation, a company in the Philippines
State Electricity Commission of Victoria, a state-owned electricity supplier in Victoria, Australia
State-owned Enterprises Commission, a government agency in Taiwan
Samsung Electronics, a multi-national corporation out of South Korea

Other usage of SEC may be found on Wikipedia at SEC