If there is no leakage of forex from official institutions then the obvious source of forex on the black market are people in the diaspora who send home US dollars through Mukuru, Western Union, Money Gram, and by means of public transport. Those who receive such money in hard currency never use the banking system but the black market.
Those who sell tobacco get some of their pay-outs in forex. Small-scale gold miners also get forex. If these guys get the forex as cash then obviously it finds its way to the black market.
Banks should never dispense forex as cash until we are able to generate enough through exports. –Goto.



