Price stability is not the only thing a central bank protects; it also guards the stability of the financial system itself. Since the 2008 crisis, financial stability has become a co-equal mandate, with its own tools and its own hard judgements. This module covers the two pillars: the lender-of-last-resort function for crises, and the macroprudential policy that tries to prevent them — with the African banking experience as the testing ground.
The lender of last resort
Bagehot's rule (1873)
Walter Bagehot's classic prescription for a central bank facing a banking panic: lend freely, to solvent institutions, against good collateral, at a penalty rate. • Freely — provide whatever liquidity the system needs, to stop a self-fulfilling panic in which fear of others withdrawing makes withdrawing rational for everyone. • To solvent institutions — rescue banks that are fundamentally sound but illiquid, NOT banks that are actually bankrupt. • Against good collateral — so the central bank is protected and is lending, not gifting. • At a penalty rate — above the normal market rate, so banks use the facility only in genuine need and have an incentive to return to private funding (and to limit moral hazard). Bagehot's rule is 150 years old and still the operating doctrine of every central bank in a crisis. Its genius is solving a coordination failure (the bank run of the clientelism/collective-action logic) by providing the liquidity that removes the reason to run.
Illiquidity versus insolvency
The hardest and most consequential judgement in a crisis is Bagehot's condition 'to solvent institutions': is this bank illiquid (sound assets, but a temporary cash crunch — rescue it) or insolvent (its assets are genuinely worth less than its liabilities — let it fail or resolve it)? The distinction is clean in theory and agonising in practice, because in a panic asset values are depressed and uncertain, so a bank that is illiquid today may be insolvent at fire-sale prices, and the central bank must judge under pressure and incomplete information. Lend to the insolvent and you waste public money and reward recklessness (moral hazard); refuse the merely illiquid and you let a solvent bank fail and the panic spread. This judgement, made in real time, is where financial-stability policy is truly tested.
Macroprudential policy
From firm-level to system-level
The lesson of 2008 was that supervising each bank's safety individually (microprudential policy) is not enough, because risks build up at the level of the system as a whole — many banks doing the same thing, fuelling a credit boom, exposed to the same shock. Macroprudential policy targets system-wide (systemic) risk: • Countercyclical capital buffers — require banks to build extra capital in booms (when credit is growing fast) to absorb losses in the bust, leaning against the credit cycle. • Borrower-based limits — caps on loan-to-value (LTV) and debt-to-income (DTI) ratios to restrain risky lending in a property boom. • The credit-to-GDP gap — a key indicator: credit growing far above its trend is the most reliable early-warning signal of a future banking crisis (Borio). • Systemic surcharges — extra requirements on the biggest, most interconnected banks whose failure would threaten the system. Macroprudential policy is inherently about leaning against the wind of a boom — politically hard (no one thanks you for ending a credit party), which is why it needs an independent, mandated authority, much like monetary policy.
The African banking experience
African banking systems test these doctrines in their own way. They are often concentrated (a few large banks), exposed to the sovereign (heavy holdings of government debt — the bank-sovereign nexus, where a sovereign-debt problem becomes a banking problem and vice versa), and prone to bouts of stress. Kenya's experience is instructive: the 2015–2016 failures of Imperial Bank, Dubai Bank, and Chase Bank tested the central bank's resolution and lender-of-last-resort judgement and the deposit-insurance system (the Kenya Deposit Insurance Corporation), and prompted reforms. The regional challenges — supervising fast-growing pan-African banking groups across borders, balancing financial inclusion (bringing in the unbanked, often via mobile money) against stability, and managing the bank-sovereign nexus as government debt rises — are live and distinctive. The Basel III international standards (higher capital and liquidity requirements) are being adopted, but adapting global frameworks to thin, concentrated, sovereign-exposed markets is its own challenge (the capability-trap warning of the Governance course).
Exercise
A mid-sized bank in a concentrated banking system faces a run after rumours of bad loans; depositors are fleeing and it has asked the central bank for emergency liquidity. Meanwhile, system-wide, private credit has been growing at twice the rate of GDP for three years, concentrated in property and government securities. (1) Apply Bagehot's rule to the failing bank, and identify the crux judgement. (2) Explain the risk of getting the illiquidity-vs-insolvency call wrong in each direction. (3) Diagnose the system-wide situation using macroprudential indicators. (4) Recommend the macroprudential response and explain why it is politically hard.