In the literature, there are works that have tried to analyze precautionary saving issues in resource
rich countries. For instance, Bems and de Carvalho Filho (2011) study these issues in a model where
investment and frictions do not play a role. Cherif and Hasanov (2012a, 2012b) also discuss these
issues but in a model with constant “golden rules” as investment decisions. Our work di"ers from
theirs by considering endogenous optimal investment decisions and other features such as absorptive
capacity and borrowing constraints.
Fourth, we investigate the role of capital scarcity for the current account dynamics, while maintaining
borrowing constraints and investment frictions. In line with the macro-development literature,
capital scarcity in our model is associated with a high marginal product of capital (van der Ploeg
and Venables, 2011a). And if the marginal product of capital is above the cost of borrowing, it becomes
optimal to use the windfall to increase public and private investment to speed up development.
This capital scarcity mechanism is di"erent from the previously discussed risk premium mechanism
that induces more investment–part of the windfall is used to repay debt, lowering the risk premium
and interest rates–and can lead to increases in investment and, therefore, to lower current account
balances.
Finally, we show how our model can be used to produce a current account norm for external sustainability
assessments in RRDCs. We calibrate the model to the Economic and Monetary Community
of Central Africa (CEMAC).6 We show that our current account norm for CEMAC falls in between
the underlying current account deÞcits and the relatively high surpluses obtained under Bems and de
Carvalho Filho (2009), which is a PIH-based approach, abstracts from investment, capital scarcity,
and credit constraints.7 These results depend, of course, on making explicit investment and its frictions.
As we assume higher absorptive capacity constraints, then our benchmark becomes closer to
the norm by Bems and de Carvalho Filho, since it becomes optimal to reduce the speed of investment