Circulation of Capital, a process of the movement of capital, in the course of which it turns from money form into commodity form, and vice versa; part of the circuit of capital in the sphere of circulation, on the capitalist market. In its movement, capital passes once through the stage of production (where it increases) and twice through the stage of circulation. In the first stage of circulation, the owner of the capital advances a certain sum of money for purchasing the means of production and labour power on the capitalist market. At this stage money capital becomes productive capital. The second circulation stage begins with the end of the production process and is in fact the process of turning the commodity form of capital into the money form. In this stage we observe the realisation of the capital value and surplus value. Capitalist production and circulation are mutually dovetailed, and one cannot function without the other. Marx pointed out: "It is therefore impossible for capital to be produced by circulation, and it is equally impossible for it to originate apart from circulation. It must have its origin in circulation and yet not in circulation" (K.Marx, Capital, Vol. I, p. 163). In the sphere of circulation, the capitalists purchase elements of productive capital (means of production and labour power) and sell marketable produce created in the production process. Capital cannot circulate without the production sphere, where labour power merges with the means of production to create value and surplus value, i. e., where capital grows of itself. The production process plays a determining role in the unity of production and circulation.