Productivity vs. Evenness in the U.S. Financial Market: A Business Ecosystem Perspective

This paper starts by presenting an empirical finding in the U.S. stock market: Between 2001 and 2021, high productivity was achieved when Shannon evenness—measuring inverse of concentration—dropped. Conversely, evenness soared, plunged. The same relationship between has been observed several ecosystems. suggests explaining this result adopting business ecosystem perspective, i.e., regarding tangle interactions companies as ecological network, which play role species. A useful strategy to model such communities is through ensembles synthetic pairwise interacting species, whose dynamics described Lotka–Volterra generalized equations. Each community specified a random interaction matrix elements are drawn from uniform distribution centered around 0. It shown that can be generated varying strength companies. When increases, increases simultaneously market decreases. decreases, decreases increases. interpreted reflecting looseness monetary policy, thus providing link interest rates structure.