The global flow of remittances declined in 2016 for the second year in a row, potentially reducing access to health care, education and food for millions of families in developing nations.
Friday's report from World Bank experts says migrants sent $429 billion from wealthy nations back to their home countries during the year. That is a drop of 2.4 percent from the previous year.
Falling oil prices in commodity exporting nations and weak economic growth in Europe took a toll on the flow of money.
India is the world's largest receiver of remittances and saw money sent home by its overseas workers fall by nearly $63 billion, a drop of nearly 9 percent. Steep declines were also reported in Bangladesh, Nigeria and Egypt.
The report says it costs about $15 on average to send a $200 remittance home, with even higher costs for destinations in sub-Saharan Africa. World Bank officials would like to cut that fee by more than half, but the effort is complicated by new rules intended to make it harder to launder money and commit other illegal acts.
The report in the Migration and Development Brief also says the number of refugees headed for Europe increased by 273,000 to a total of 1.6 million. Globally, refugee flows rose by 1.4 million to a total of 16.5 million.
The lead author of the brief says migration will "almost certainly" increase due to large income gaps, widespread youth unemployment, climate change, fragility and conflict. Dilip Ratha of the World Bank says migration is also being driven by aging populations in wealthy nations. As developed nations lose workers to retirement, new employees may be needed to fill those gaps.