  Adapting a simple biological model, we study the effects of control on the
market. Companies are depicted as sites on a lattice and labelled by a fitness
parameter (some `company-size' indicator). The chance of survival of a company
on the market at any given time is related to its fitness, its position on the
lattice and on some particular external influence, which may be considered to
represent regulation from governments or central banks. The latter is rendered
as a penalty for companies which show a very fast betterment in fitness space.
As a result, we find that the introduction of regulation on the market
contributes to lower the average fitness of companies.
