A government-funded study in Italy has revealed the country's mafia makes less money than widely believed.
The Catholic University of the Sacred Heart in Milan's study shows it only earns a tiny fraction of Italy's income - not the 10% that was thought.
The report looked at illegal activities like drug smuggling, extortion and business-world penetration.
An anti-mafia group, however, says despite many studies into mafia money, it is "not easy to quantify".
The report by the university in Milan takes aim at what it says is a tendency to exaggerate the mafia's wealth.
It says the frequent suggestion in the media that the mafia creates the equivalent of 10% of Italy's GDP (gross domestic product) is far from true - the figure is actually less than 1%.
Getting the message out that the mafia is not performing as well financially - and is not as powerful - as is sometimes believed is important, the report says.
But even if the mafiosi are not making as much as was thought, their profits are still vast, says the BBC's Alan Johnston in Rome.
They earn as much as $13bn (£8.1bn) a year in Italy, the study says, adding that Italy's mafia are also active in other countries like China, Iraq and Afghanistan.
But Marcello Cozzi, vice-president of Libera, a main anti-mafia organisation in Italy, says the mafia does not do business that is easily quantified.
"We must say this: it's not easy to quantify the turnover of the mafia. It's not a business in which there are receipts and invoices. So any study that is made about the mafia business is [approximate]."
He added that several studies have been done and that there have been different estimates.
"We are speaking of an underground sector," he said. "We know that wherever there are big business possibilities, the mafia is always there."