Buenos Aires Nations Cup this year
There is a write up in the current COTH. I found it rather interesting that only three nations fielded teams. The Argentines had two, the US had one, and IIRC the Canadians were the other.
The Brazilians who are next door and will be hosting the next Olympics, didn't bother to send a team. Not sure why this distresses me , but it does. Of course it's really none of my business, but it just seems that they could have made the effort to support horse sports in South America.