Patent ambush
A patent ambush occurs when a member of a standard-setting organization, while participating in development and setting a standard, withholds information about a patent that they or their company owns, has pending, or intends to file (and which is relevant to the standard), and the company subsequently asserts that it is infringed by use of the standard as adopted. Standards-setting organizations, such as the IEEE and ANSI, typically require each member of their standard-setting committees to file letters with them that either deny knowledge of company patents that are relevant to the standard, or identify the patents they do know about.