On the black market at 8: 1.

Then this attracts foreign exchange speculators. It is more profitable to sell on the black market than to buy from the bank.

Most of the demanders in the black market are illegal income, and it is risky to exchange it in formal channels, so they enter the black market.

The demanders give money to the managers of the black market and let them exchange it. Managers withdraw operating expenses in the middle.