Central Bank governor John Mangudya said Cash Twenty-Four, a bureau de change; and Crediconnect, a credit-only microfinance institution, had been suspended with immediate effect pending further investigations.
Mangudya said that the two institutions can have their licences cancelled if found guilty or they can face criminal charges.
Zimbabwe has been experiencing a serious raid on its local currency since June last year when it made the local currency the sole legal tender for local transactions.
It allowed businesses to trade in other currencies, mainly the United States dollar last month to help mitigate against the effects of the coronavirus pandemic.
Rates on the black market started appreciating after the lockdown which began on 30 March but they have since fallen to pre-lockdown levels.