A report says pirates operating in the waters off the Horn of Africa have netted about $US400 million in ransom payments since 2005 and the money has funded a range of criminal activities worldwide.
The study, carried out by the World Bank and the United Nations, says the piracy is funding the illegal weapons trade and human trafficking, militias and money laundering.
It says the financiers behind the piracy, and not the pirates themselves, collect most of the cash, the BBC reports.
Co-author Stuart Yikona says the money has been funnelled into both legitimate and illegitimate activities.
The legitimate activities include hotels, restaurants and projects in the transport sector.
The report recommends a range of ways to combat the problem, including anti-money laundering measures.
