On 31 January 2017, the BCA published an informal information guide on bid rigging practices, which is aimed as a tool for public authorities. Bid rigging is a form of cartel whereby competitors collude in their response to a public tender and is a criminal offence under Belgian law.

The guide issued by the BCA is in line with the BCA's focus on public procurement as announced in the BCA's fourth note on enforcement priorities. In the guide, the BCA first explains why public authorities are a "perfect target" for cartelists given the size of purchases and the administrative requirements in public procurement procedures.

The guide then provides practical explanations on the concept of bid rigging in its different forms (cover bidding, bid suppression, bid rotation, etc…) and an overview of warning signs to help purchasing managers to recognise suspicious behaviour that could reveal potential bid rigging. These warning signs can for instance relate to the bid (e.g. each bidder seems to win in turn or the winning bidder does not accept the contract, and becomes a subcontractor later on), the response to a tender (e.g. the same spelling or calculation errors), the price (e.g. a big difference between the price submitted by the winning bidder and the losing bidder or sudden identical price increases) or to statements from bidders (e.g. references to the fact that a competing bidder was not allowed to issue an offer or to customer allocation).

The guide also indicates which market conditions can facilitate bid rigging and sets out preventive steps that can be taken by public authorities to avoid bid rigging.