The hard-core reality is that a 0.0% interest rate to borrowers is non-sustainable. Someone is paying the cost of Mekong Plus operations. Unfortunately, we're not informed who that is. Considering they are a five-star field partner, something is amiss. Personally, I don't consider this to be an acceptable level of communication to Kiva lenders.
They attract plenty of support from mainly France, Belgium & Holland, but also Canada, the EU etc - long list of reputable donors and supporters
here on their shared (with Viet Nam Plus) website. Seems Mekong Plus is the Belgian side of the operation, Viet Nam Plus the French. They solicit contributions from individuals.
I notice their loans are
extremely small - you have to go to page 33 of 33 in the
list of their loans sorted by amount to find one over $100, and the average for active loans is $74.
So, extremely small loans to extremely poor people, by what appears to be essentially a well-intentioned charitable NGO rather than a "proper" MFI. In that light the 0% interest rate seems to me to be fair enough, even if you have to dig a bit to piece it all together.
~~ Peter