The WSJ has a piece today about the worldwide remittances market. It is roughly $554 Billion worldwide with the top recipient countries (no particular order)

1. India $46B (from US, Dubai and Saudi Arabia), 3% of GDP
2. Mexico $38B (from US primarily), making up 3% of GDP
3. China $24B (<1% of GDP)
4. Pakistan $11B (8% of GDP)
5. Philippines $20B (10% of GDP)
6. Guatemala $10B
7. Vietnam $12B
8. Bangladesh $15B
9. Ukraine $11B
10. Egypt $9B
11. Nigeria $8B

The market was largely owned by Western Union, but now a host of startups are in the space including:

1. Transfer Wise
2. Xoom
3. Remitly
4. Money Gram
5. Ria