Should countries share a currency? Africa has both a long-standing monetary union (the CFA franc zone) and ambitious plans for more (the East African Community's monetary-union project, the broader continental aspiration). This module covers the theory of when a shared currency makes sense — optimum-currency-area theory — and applies it to the African cases, with the cautionary lessons of the euro in view.
Optimum-currency-area theory
When should countries share a currency? (Mundell 1961)
Robert Mundell's optimum-currency-area (OCA) theory asks when a group of regions or countries is better off sharing a single currency (giving up the exchange rate between them) than keeping separate currencies. Sharing a currency brings benefits (lower transaction costs, eliminated exchange-rate uncertainty, more trade and integration, imported credibility) but costs the members their independent monetary policy and the exchange rate as a shock-absorber between them. The criteria for a region to be a good OCA — for the benefits to outweigh the costs — are: • Labour mobility — workers can move from a depressed region to a booming one, substituting for the lost exchange-rate adjustment. • Fiscal transfers / risk-sharing — a central budget can transfer resources to a region hit by an adverse shock. • Business-cycle synchronisation (shock symmetry) — if the members' economies move together, a single monetary policy suits them all; if shocks are asymmetric (one booming, one busting), a single policy can't help both. • Openness and trade integration — the more the members trade with each other, the greater the benefit of a shared currency and the less they need an exchange rate between them. • Production diversification — diversified economies face smaller idiosyncratic shocks. The more these criteria are met, the better a currency union works; the less, the more the members will suffer from being unable to adjust to region-specific shocks (the euro crisis being the great cautionary example — a union of economies that met the criteria only partially).
The endogeneity critique
Frankel and Rose (1998) added an important twist: the OCA criteria are partly endogenous — they can be satisfied BY the currency union itself, not just beforehand. Sharing a currency boosts trade among members (no exchange-rate risk, lower costs), and more trade tends to synchronise their business cycles — so a group that doesn't quite meet the criteria ex ante might come to meet them ex post, after forming the union. This is an argument for optimism about currency unions (form it, and integration will follow). But the euro experience tempers it: the union also concentrated specialisation and divergence in some respects, and the criteria did not converge enough to prevent the crisis — so endogeneity is real but not guaranteed to rescue a poorly-matched union. The lesson: a currency union is partly self-justifying through the integration it creates, but counting on endogeneity to fix a fundamentally ill-suited union is a gamble.
The CFA franc zone
Africa's existing monetary union
The CFA franc zone comprises two monetary unions (West and Central African) of mostly former French colonies, sharing currencies pegged to the euro (formerly the French franc) with a French treasury guarantee of convertibility. The benefits are real: low and stable inflation (the peg imports the ECB's credibility — a credibility many members could not achieve alone), monetary stability, and regional integration. The criticisms are equally real and increasingly vocal: the peg can leave the currency overvalued (hurting export competitiveness, especially for commodity exporters whose terms of trade swing), members surrender monetary policy entirely (to the ECB, whose policy suits the euro area, not the Sahel — an asymmetric-shock problem), and the arrangement carries a colonial legacy (French oversight, reserves historically held in France) that has made it politically contentious. The recent reforms and the proposed transition to a new currency ('the eco') reflect the tension between the stability the peg provides and the autonomy and legitimacy the members want. The CFA zone is a real-world test of the OCA trade-off: it delivers stability at the cost of adjustment capacity and autonomy, and whether that bargain is worth it is genuinely debated.
The EAC monetary-union ambition
The East African Community (Kenya, Tanzania, Uganda, Rwanda, Burundi, South Sudan, DRC) has a long-standing ambition for a monetary union, with a protocol and convergence criteria (on inflation, deficits, debt, reserves) that members are meant to meet before adopting a single currency — a timeline that has repeatedly slipped. Assessing the EAC against the OCA criteria gives a mixed picture: intra-regional trade is growing but still modest (limited openness to each other), the economies are somewhat diverse but face some common shocks (commodity prices, weather), labour mobility is improving but limited, and there is no central fiscal capacity for transfers. The euro's lesson looms large: a monetary union without a fiscal union and sufficient convergence is fragile (the euro crisis showed that a single monetary policy plus separate fiscal policies, without transfers or banking union, can produce divergence and crisis). The prudent reading: the EAC is not yet a strong OCA, the convergence criteria are the right idea (build the preconditions first), the slipping timeline reflects genuine unreadiness rather than mere foot-dragging, and rushing into a union before the criteria (and ideally some fiscal risk-sharing) are met would risk importing the euro's problems. Monetary integration is a worthy long-run goal that should follow, not precede, real economic convergence and integration.
Exercise
The East African Community is debating whether to launch its long-planned monetary union on a fixed timeline, or to wait until convergence criteria are met. A proponent argues, 'A shared currency will boost trade and integration, and the criteria will be satisfied once we form the union anyway.' (1) Assess the EAC against the OCA criteria. (2) Explain the proponent's argument using endogeneity, and its limits. (3) Use the euro crisis to identify the key missing element and the risk of rushing. (4) Recommend a sequencing and justify it.