The South African government did attempt to restrict the damaging outflow of capital. Knight writes that "in September 1985 it imposed a system of exchange control and a debt repayments standstill. Under exchange control, South African residents are generally prohibited from removing capital from the country and foreign investors can only remove investments via the financial rand, which is traded at a 20% to 40% discount compared to the commercial rand. This means companies that disinvest get significantly fewer dollars for the capital they withdraw."