In this paper, we consider the dynamics of a global supply chain network economy in the presence of risk and uncertainty. In particular, we assume three tiers of decision-makers: manufacturers, distributors, and retailers, who acquire the product in order to satisfy the demand at the demand markets. The manufacturers, distributors, and retailers may be based in the same or in different countries and may transact in different currencies. We allow for electronic transactions in the form of electronic commerce between the manufacturers and the retailers as well as between the distributors and the retailers since the retailers may be physical or virtual. In addition, supply-side risk and demand-side risk are handled in our formulation with the former being expressed as a multicriteria decision-making problem for each manufacturer and distributor (with distinct weights associated with the criteria) and the latter being handled with the use of uncertain demands. The proposed framework allows for the modelling and theoretical analysis of such global supply chain supernetworks, which involve competition within a tier of decision-makers but cooperation between tiers, as well as the dynamic tracking of the evolution of the associated prices and product transactions to the equilibrium state. Numerical examples are provided for illustrative purposes.