Money sent back home by migrants far exceeds international aid given to developing countries, a study suggests.
Migrants typically send home $100, $200 or $300 at a time
About 150 million migrant workers sent more than $300bn (£147.3bn) home in 2006, says the International Fund For Agricultural Development (IFAD).
That compared with $104bn in aid from donor nations and direct foreign investment of $167bn.
Asia led the remittance table, receiving $114bn, followed by Latin America and the Caribbean.
The report, compiled in collaboration with the Inter-American Development Bank (IDB), based its findings on official data from governments, banks and money transfer operators.
Hailed as the first study to quantify both formal and informal remittance channels, it also examined informal cash flows such as money carried home.
IFAD said about a third of the cash sent home by migrants went to rural areas, where poverty tends to be worse than in cities.
Most remittances are used to buy basic necessities, such as food, clothes and medicine, the study found.
However, of the 10% to 20% that is saved, most is hidden away in the home - in cooking pots and under mattresses - rather than put to work in savings accounts.
IFAD warned this "missed opportunity" meant that local communities failed to benefit from opportunities for economic development.
"One of our priorities is to improve poor people's options by finding ways to cut transaction costs and link remittances to other financial services, such as savings, investments and loans," said IFAD assistant president Kevin Cleaver.
While more companies are trying to get a slice of the business of sending remittances overseas, few banks are offering recipients the chance to make the most from their money, the report added.
With approximately 10% of the world population receiving remittances, the IDB has been encouraging microfinance institutions, credit unions and banks to provide lower-cost remittance services.
Asia: More than $114bn
Latin America & the Caribbean: $68bn
Eastern Europe: $51bn
Near East: $29bn
SOURCE: IFAD & IDB report, figures for 2006
Both the IDB and IFAD ague that by offering more detailed data on the practice, more "players" will be attracted to the market, thereby increasing competition and driving down costs.
Latin America and the Caribbean consumers have benefited from such developments in the remittance market, but mainly in major urban areas, the IDB said.
Elsewhere, new technology is helping to change the sector. For example, mobile phone technology is increasingly used for money transfers to India and the Philippines and is "growing exponentially".
"For IFAD, the most important thing is to look at how to channel this money so that it contributes to prosperity in rural areas," added Mr Cleaver.
"It's always been harder to expand financial services beyond cities," said Donald F Terry, the report's co-author and assistant general manager of IDB's Multilateral Investment Fund.
He added the group was examining ways to improve poorer people's access to such services and to cut their costs.