What impact do small and mid-sized money transmitters have on the global remittance market—are they insignificant, and what data exists on their combined share?

They are very much relevant, albeit now facing various hurdles. As Katie Koroleva cites, the number varies. I’ve seen it as low as 5% and as high as 50%. However, they average out between a fifth (20%) to a quarter (25) of the market share.

These numbers are now on the decline due to issues like derisking/access to banking, OMTOs (Online Money Transfer Operators), technology, compliance, corridor offering, pre-funding capital issues, etc.

The industry will eventually mimic the same way the online industry presents itself. A few dominant players and a few niche players. Everyone else would wither away.

There are no official statistics around this.