We examine the connective architecture of the main Colombian payment and settlement systems in order to update what we know about local financial networks, and to elaborate on the main consequences for financial stability. Evidence suggests that local financial networks display a modular (i.e. clustered) scale-free (i.e. inhomogeneous) architecture. Results concur with other real-world networks, and propose new insights and challenges for authorities contributing to financial stability. For instance, (i) traditional reductionist assumptions for modeling financial systems (e.g. homogeneity) may be particularly misleading; (ii) the observed modular scale-free architecture favors robustness and resilience; (iii) the generating process of such architecture overlaps with literature on trading relationships; (iv) carelessly reducing inhomogeneity in financial systems may backfire in the form of a less robust and less resilient financial system; and (v) financial authorities should understand and take advantage of the existing architecture by means of designing and implementing macro-prudential regulation and system-calibrated requirements.

An interdependent network coupling financial institutions’ multiplex (i.e. multi-layer) and financial market infrastructures’ single-layer networks gives a more accurate picture of a financial system's true connective architecture. We examine and compare the main properties of Colombian multiplex and interdependent financial networks. Coupling financial institutions’ multiplex networks with financial market infrastructures’ networks removes modularity, which augments financial instability because the network then fails to isolate feedbacks and limit cascades while it retains its robust-yet-fragile features. Moreover, our analysis highlights the relevance of infrastructure-related systemic risk, corresponding to the effects caused by the improper functioning of financial market infrastructures or by financial market infrastructures acting as conduits for contagion.