It's illegal for companies to carve up a market, collude on bids or fix pricing.

FORBES: Magazine Article

It would be unseemly for law firms to collude on their billable rates in an antitrust case.

FORBES: How Many Law Firms Does It Take To Sue An Egg Company? 34, Apparently

In return, the sole flag carrier of the small country at the other end is allowed to collude on fares and capacity with its chosen American partner, without being clobbered by antitrust law.

ECONOMIST: Airlines

Under your plan, instead of receiving Medicare benefits when I am old and frail should I expect to figure out how to purchase insurance from a cartel of companies that are protected by the Federal government and allowed to collude on predatory pricing schemes?

FORBES: Congressman Ryan, Should Predatory Pricing Cartels Really Run Health Care?

First, it underlines that, with a more open system in the Commons, it is no longer possible for governments and Oppositions to collude to prevent prime-time debates on euro-issues.

BBC: Backbench muscle

America's Department of Transportation (DoT), which has some antitrust powers, has not only given its blessing to the rise of alliances, but actually requires airlines to collude fully within each of their groupings, and to share costs and agree on prices.

ECONOMIST: Airline alliances