bid rigging
noun [ U ]
LAW ukusillegal behaviour by companies that are competing for work in which they make a secret agreement, for example to increase their prices or to share the work, in order that they both gain financially:
The Office of Fair Trading has today formally accused 112 construction firms in England of participating in bid rigging.
illegal behaviour by two or more people at an auction (= public sale) in which they agree not to bid against each other