  This paper describes surface-like waves of macroeconomic Credits-Loans
transactions on economic space. We use agent's risk ratings as their
coordinates and describe evolution of macro variables by transactions between
agents. Aggregations of agent's variables with risk coordinates x on economic
space define macro variables as function of x. Aggregations of transactions
between agents at point x and y determine functions of two variables (x,y) on
economic space. As example we study Credits transactions provided from agents
at point x to agents at point y and thus amount of Loans received by agents at
point y from agents at point x at moment t during time term dt. We model
evolution of macro transactions by hydrodynamic-like equations. Agents fill
macro domain on economic space that is bounded by minimum risk ratings of most
secure and maximum risk ratings of most risky agents. Economic and financial
shocks can disturb steady borders of macro domain and cause perturbations of
transactions. Such disturbances can generate waves that can propagate along
risk borders alike to surface waves in fluids. As example, we describe simple
model interactions between two transactions by hydrodynamic like equations in a
closed form. We introduce notions of "macro accelerations" and their potentials
that establish steady state distributions of transactions on economic space.
For this model in linear approximation we describe surface-like waves and show
that perturbations induced by surface-like waves can exponentially grow up
inside macro domain and induce macro instabilities in a low risk area.
Description of possible steady state distributions of transactions and
surface-like waves on economic space might be important for macro modeling and
policy-making.
