Out of curiousity where does this money come from? Reason, most times when other countries provide investment capital for infrastructure projects, they are looking for either a stronghold on the resource (if applicable) or provide jobs for their companies doing the construction. This is proven worldwide by China escpecially in the billion dollar projects they do in Africa.
All in all this is a good thing for both parties (countries) as the receiving country realizes the new infrastructure upgrade even if they dont get the tender for construction.
Companies like Odebrecht and others of foreign source obtain soft loan approvals to carry out projects in the region or other side of the world from local (Brazil) financing sources, which include their country's own import/export bank to bid and carry out the works.
The profit for them is that the DR has never defaulted on a single collateral loan of public infrastructure. So even when the work is carried out under the soft terms, they get paid on the spot by their financing source minus a very minimal escrow amount from the payment for financial safety under the financial institution's terms.
The profit for the financing part, even when they are soft loans over a mid to long term, is the level of interest charged. This amount will always surpass many of the private investments in their portfolios and balance the mid to long term risks of the institution.
Dominican companies are not worried about the competition on these tenders, as they have more than enough tenders to look for from other public works year round. As a matter of fact, relating to the same foreign companies winning the tenders, they are mandated by LAW to have local participation of local contractors and companies to carry out the works. Case in point the Autopista El Coral, Corredor Duarte and many other major works carried out by foreign companies, alongside the locals, which didn't need to secured the funds in the first place!
The cash cow for companies like the one listed above, is that they set a foothold in the country with minimal direct foreign investment. They use the profits to cement their companies in the country and further their contracts within the private sector via partnerships with other local companies. After a while, they're able to carry out self financed private projects in the country with minimal exposure and high returns, beyond the one they could get as an outsider.
Just recently many U.S. based construction firms have been very active in the DR via these types of contracts, but from the private sector. Most of the largest projects carried out in the country so far, have been done with foreign companies involvement to some degree.
It's not the other country's that are looking to invest, but their biz sector with ample support from their own financial sectors including the public financial institutions that need a stable portfolio.