Recognising the pattern behind bid rigging
Launch library · evergreen read
Bid rigging is a collusive pattern where competitors who are supposed to be bidding against each other secretly agree on who will win, and at what price, before a tender is even submitted. The tender still looks competitive on paper, which is exactly what makes the pattern difficult to spot without close comparison across bids.
Typical signs include suspiciously similar pricing structures between supposedly independent bidders, a rotation where the same group of firms take turns winning, or a losing bid priced so high it looks designed to lose rather than to win. Complementary bidding, where one firm submits a deliberately weak bid to make another look competitive, follows the same underlying logic.
Because the scheme depends on communication between bidders, procurement teams are often trained to watch for informal contact windows, shared personnel between competing firms, or bid documents that share unusual formatting or wording. None of these signs proves collusion alone, but together they are enough to justify a closer look.