# How do I use a monopsony (product market) graph to show that a firm has more buying power over a supplier?

For instance, Tesco has more buying power over British farmers. How would I show this on a monopsony graph where Tesco has a surplus?

I am not sure what you mean by a monopsony graph. If you mean a graph wherein you show that Marginal Factor cost is not equal to the inverse input supply curve, then you do not need the graph at all. The fact that $$MFC(x) \neq w_x$$ shows that the buyer has market power.