Cocaine is big business in Europe these days, according to experts with the U.S. Drug Enforcement Administration (DEA). Boatloads of blow float across the Atlantic Ocean from South America, only to float back as illicit money, which finds its way to states such as Delaware.

But whose pockets does the cash end up in? That’s an investigative dead-end.

“When I worked at the U.S. Treasury’s FinCEN (which combats money laundering), we used to get requests from many countries regarding drug cases where the trail went to Delaware,” said former Special Agent John Cassara. “It was impossible to follow the paper trails in those cases.”

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Why is that? “Delaware and other havens in the U.S. do not have beneficial ownership information,” he said.

“Beneficial ownership” sounds complicated but is actually very simple: It tells you who is the real owner. When you buy a house, your name is on the deed. Buy Apple stock, and you own a small piece of this multinational technology company.

But an anonymous shell corporation allows its owners to trick the system. By definition, a shell corporation is really a ghost. It doesn’t have any significant assets or operations of its own. It doesn’t make anything or collect money for having made it.

It’s generally used as a “pass through” to allow another company or business to smoothly move financial assets from one place to another, such as from a foreign country to the U.S. Or it may simply serve as a “sleeper cell,” sitting dormant until its owners need it.

None of this is illegal, and many U.S. major companies have set up and use shell corporations.

But shells do lend themselves to illegal activity, because drug lords and terrorists know they can freely move money back and forth, often between two, three or more shells to create a financial hall of mirrors before the funds reach their destination.

What makes them a challenge for law enforcement -- like the DEA and U.S. Treasury Department, is that so many states allow the real owners to remain anonymous. In states like Delaware, Nevada and Wyoming, “you need less information to start a shell corporation than you do to get a library card,” claimed Nathan Proctor, a director of Fair Share, a Washington, D.C.-based consumer group.

This makes shells the ideal way to not only hide money but to “wash” it -- turn it from illegal bribes or drug payoffs into legitimate business enterprises like New York City apartment houses. The topic was spotlighted by a recent CBS “60 Minutes” expose in which a representative of a fake African official was able to get more than a dozen law firms to give him advice on how to set up a shell corporation.

Crime novels about the Cayman Islands don’t compare to the U.S., which is actually one of the easiest places to hide money, put it back in the system and coincidentally, avoid paying taxes, according to investigators.

How much money? The Office of National Drug Control Policy pegs it at $65 billion. Since all federal agencies seize only $1 billion, busting street-level dealers is an ineffective “game of whack-a-mole,” said Proctor. So much slush money is flowing through the pipes that if one pusher is taken out, another is financed.

A report by Fair Share, called “Anonymity Overdose,” describes how the system worked for the few drug lords whose deals have been uncovered. Mexico’s Los Zetas cartel used its anonymous shell company to buy racehorses, one of which it named “Number One Cartel.” Busted for using call girls to transport oxycodone, Kingsley Iyare Osemwengie named his shell company “High Profit Investments LLC.”

The U.S. Treasury is on to this anonymous shell scheme. Secretary Jacob Lew is not only tightening his agency’s regulations, but in a May 5 letter to House Speaker Paul Ryan he urged Congress to pass a “common-sense requirement” to make sure banks and other financial institutions know the actual “beneficial owner” of these shell companies before the institutions do business with them.

The Clearing House Association, a payments and advocacy organization owned by some of the world’s largest banks, backs the proposed measure.

But disclosure of these anonymous shells has some powerful opponents. States like Delaware get huge revenues from setting up corporations -- especially shell corporations -- at minimal cost to the state, according to The New York Times.

In a 2012 expose, The Times said Delaware, operating from a small office building, had collected $860 million in taxes and fees from its absentee corporate residents during the previous year. “Delaware had more corporate entities, public and private, than people,” the paper noted.

States such as Nevada and Wyoming are also moving into this arena. Ironically, these same states spend hundreds of millions to catch and imprison drug felons and even more to rehabilitate victims of opioid overdoses, which now kill more people than car crashes.

But the main opponent of naming the real owners of every corporation is the American Bar Association (ABA). In a May 24 letter to two congressmen, ABA President Paula Brown said the legislation would subject lawyers to the Bank Secrecy Act and undermine “attorney-client privilege,” or the confidential relationship that lawyers have with their clients. The ABA also said such a law would interfere with state court regulation of the legal profession.

The ABA and Brown felt that the definition of a “beneficial owner” was overly broad and would also impose burdensome regulations on states by requiring them to obtain information on each company, keep it current and make it available to law enforcement. (The Senate version of the bill does provide some funding to do this.)

Patrick Fallon Jr., head of the FBI’s financial crimes section, disagreed. “I can’t think of a reason not to do that,” he told the McClatchy newspaper syndicate, saying it was the “most simplistic way” to resolve the problem.

But would it? Drug cartels are loaded with lawyers, accountants and the money to bribe public officials, and they’re resourceful chameleons, said DEA spokesperson Russ Baer.

“We do go after the head of the snake, and we’ve been very successful in stopping money laundering operations by terrorist groups like Hezbollah,” he said.

But anonymous shells are only one piece of the puzzle. In a typical transaction, drugs may move from Colombia to Africa and then to France, handled each step of the way by a “transfer of value” between Lebanese money brokers who are entrenched in legitimate businesses.

The money earned is laundered back into U.S. dollars through a scheme such as selling a boatload of used cars worth $1 million, but paid for with drug profits of $5 million.

The extra dollars are then marketed on the “black market peso exchange,​” which puts the money back in the pockets of the Colombian drug kingpins.

“It’s an intensive paper shuffle,” Baer admitted. “But knowing the owners of these anonymous corporations would help to disrupt this chain.”