From Longman Business Dictionary
conspiracycon·spi·ra·cy /kənˈspɪrəsi/ noun (plural conspiracies) [countableC, uncountableU] a secret plan that is made by two or more people to do something harmful or illegalconspiracy to do somethingAll three men were charged with conspiracy to defraud.
a conspiracy against something/somebodyThe company appears to be looking for proof of an industry-wide conspiracy against it.