Bid Rigging

Bid rigging is an agreement among competing bidders that decides the winner of a competitive bid before the buyer opens the bids. The bidders still submit prices, so the process looks competitive, but the "lowest" bid is set by the group and is higher than open competition would produce. In the United States, bid rigging is a felony under the Sherman Act, punishable by up to 10 years in prison and fines up to $1 million for individuals and $100 million for companies, according to the Federal Trade Commission.

This page defines bid rigging, walks through the four schemes the U.S. Department of Justice prosecutes most, and turns the DOJ's red-flag list into checks a small procurement team can run on its own RFQ results.

What is bid rigging under the law?

The FTC describes bid rigging as coordination among bidders whenever business contracts are awarded by soliciting competitive bids. The DOJ Antitrust Division primer for procurement officials puts it more bluntly: bid rigging is fraud which involves bidding, an agreement among competitors as to who will be the winning bidder.

Three legal points matter for buyers:

• It is a per se violation. Once the agreement is proven, the conspirators cannot defend it by arguing the agreed prices were reasonable.
• No written contract is needed. The DOJ can prove the agreement with circumstantial evidence such as suspicious bid patterns, phone records and expense reports.
• The DOJ can prosecute conduct that happened at least in part within the past 5 years, and victims can sue for up to 3 times the damages they suffered.

Bid rigging is illegal in most countries, not only the U.S. It applies to private RFQs as well as public tenders: any time you ask several suppliers to quote, the suppliers can collude.

What are the types of bid rigging schemes?

The DOJ groups most cases into four schemes. Many real cases combine two or more.

Subcontracting is the usual glue. A firm that agrees to lose often gets a subcontract or supply deal from the winner. The DOJ lists three forms of payback: a promise to win a later contract (the most common), a subcontract, or a direct payment disguised as a legitimate invoice.

Wikipedia's entry on bid rigging adds the forms that involve the buyer's own staff: leaking one bidder's price to another, writing specifications only one supplier can meet, and splitting a purchase into smaller orders to keep each under the approval threshold that would trigger competitive bidding.

What are the red flags of bid rigging in RFQ results?

The DOJ's list of suspicious indicators maps directly onto a quote comparison table. Here are the checks worth running every time a round closes:

1. Identical prices. Two suppliers quote the same unit price on individual line items or the same lump sum.
2. Equal gaps. The quotes step up by the same increment, for example 3% between each supplier.
3. One realistic bid. A clear gap between the lowest quote and all the others, which the DOJ calls a "number-to-bid-above" pattern.
4. Everyone high. All quotes land well above your estimate or above what the same suppliers quoted elsewhere, especially when work is scarce.
5. Odd line items. One supplier is much higher on some lines and inexplicably low on others, as if the contract were being split.
6. Missing bidders. A qualified supplier that downloaded the RFQ or asked questions never submits.
7. Same order on re-bid. When you re-run an RFQ because all prices were too high, the suppliers come back in the same rank order.
8. Shared fingerprints. Quotes with the same spelling mistakes, the same formatting or the same math errors.
9. Winner subcontracts losers. After award, the winning supplier hands part of the work to a supplier that lost.
10. Prices drop when a newcomer bids. A new supplier joins and the incumbents suddenly get cheaper.

Worked example: what a cover-bid round looks like

An illustrative RFQ for 5,000 machined brackets, quotes due in 7 days, with an internal estimate of $4.10 per unit:

No single row proves anything. Together they hit flags 2, 3, 4 and 6: every quote is above estimate, the losers step up by the same 10%, one loser is non-compliant, and a qualified supplier went silent. That is a round to re-run with 2 or 3 new suppliers invited, not one to award on autopilot.

Over several rounds, look for payback patterns: a supplier that always bids and never wins, suppliers that win an equal number or value of contracts, or a territorial split you could draw on a map.

A caution from the DOJ itself: these indicators are not proof. A quote far above your estimate may mean your estimate was wrong, and a supplier can lawfully submit a high bid because it is too busy but wants to stay on your list. Only an agreement between competitors makes it illegal.

When is bid rigging more likely?

The DOJ names the market conditions that make collusion easier. The red flags above deserve more weight when:

• There are few suppliers, or a few large ones plus small fringe players.
• The item is standardized, so price is the only thing left to compete on.
• Your specification is restrictive and has no substitutes.
• You buy the same thing repeatedly from the same pool, so suppliers learn who bids.
• The suppliers know each other through trade associations, social ties or staff moving between firms.

How can a buyer prevent bid rigging?

The DOJ's first recommendation to procurement officials is to expand the bidder list: invite as many suppliers as is economically reasonable, because every extra bidder makes a cartel harder to hold together. Practical steps for an SMB team:

• Add new suppliers each round. Even one outside bidder breaks a rotation.
• Keep bidder identities private. If suppliers cannot see who else was invited, they cannot coordinate as easily. In AuraVMS, anonymous bidding keeps supplier responses private from each other.
• Compare quotes line by line, not only totals. Identical line prices and equal increments hide inside a total. A side-by-side quote comparison with L1, L2, L3 price ranking makes these patterns visible; the judgment is still yours.
• Keep history. Rotation and allocation only show up across rounds, so keep every RFQ's quotes, not just the winner.
• Write an independent estimate before you open quotes, and use a sealed bid deadline so nobody can adjust after seeing others.
• Ask for a certificate of independent price determination, a signed statement that the price was arrived at independently. Public agencies use it; private buyers can add it to the RFQ terms.

If you suspect collusion, do not confront the suppliers. Keep the documents and report it: in the U.S. the DOJ Antitrust Division and the FTC both take complaints.

Frequently asked questions

Is bid rigging a crime?

Yes. In the U.S. it is a felony under the Sherman Act, with up to 10 years in prison, fines up to $1 million for individuals and $100 million for companies, or twice the gain or loss from the offense.

What is the difference between bid rigging and price fixing?

Price fixing is an agreement on prices in general, such as a shared minimum price. Bid rigging is an agreement on who wins a specific competitive bid. Both are per se illegal.

What is complementary bidding?

Also called cover or courtesy bidding, it is when some bidders submit deliberately high or non-compliant quotes so a chosen competitor wins while the process still looks competitive.

Can a buyer's employee be involved in bid rigging?

Yes. Leaking one supplier's price to another, tailoring specifications to one supplier, or splitting orders to stay under a bidding threshold are all forms of bid rigging that involve the buyer's own staff.

Does a high bid always mean collusion?

No. The DOJ says an intentionally high bid made for independent business reasons, such as being at capacity, is lawful. Only an agreement between competitors is illegal.