Very simple.
Lets just talk about $1,000,000 pesos and above. Less than that is just a waste of time.
Most banks in DR today are giving you 20% tops on fixed certificates for two months or more up to a year. The best bet is to stick to 90 days, so you can have the option to play around and flexibilize your options. Of course rates could go down and you may lose a few points, but right now its an up market.
If you try places like Cotisa and Bolsa de Valores which deal with commercial paper, they are paying about 24% a year using companies like Hache, Leasing Popular, Hizzpizza, De Moya Construction, Ciudad Satelite, several car leasing companies, etc.
TW