What is 'Collusive bidding'? In which ways collusive bidding may occur?

Bidding, as a practice, is intended to enable the procurement of goods or services on the most favourable terms and conditions. Invitation of bids is resorted to both by Government (and Government entities) and private bodies (companies, corporations, etc.). But the objective of securing the most favourable prices and conditions may be negated if the prospective bidders collude or act in concert. Such collusive bidding or bid rigging contravenes the very purpose of inviting tenders and is inherently anti-competitive. Some of the most commonly adopted ways in which collusive bidding or bid rigging may occur are: Agreements to submit identical bids Agreements as to who shall submit the lowest bid, agreements for the submission of cover bids (voluntarily inflated bids) Agreements not to bid against each other Agreements on common norms to calculate prices or terms of bids Agreements to squeeze out outside bidders Agreements designating bid winners in advance on a rotational basis, or on a geographical or customer allocation basis.