Bank Runs and Panics: A Primer

A bank promises its clients immediate access to cash. Depositors can redeem their funds on demand at face value—first come, first served. Other short-term creditors can do the same, albeit at varying speeds, by not rolling over their loans. And, households and firms that pay a fee for a credit commitment can take down their loans at will.

For banks that hold illiquid assets, these promises of liquidity on demand are the key source of vulnerability. The same applies to other financial institutions (de facto or shadow banks) that perform bank-like services, using their balance sheets to transform illiquid, longer-maturity, risky assets into liquid, short-maturity, low-risk liabilities.

A bank run occurs when depositors wish to make a large volume of withdrawals all at once. A bank that cannot meet this sudden demand fails. Even solvent banks—those whose assets exceed the value of their liabilities—fail if they cannot convert their assets into cash rapidly enough (and with minimal loss) to satisfy their clients’ demands. A banking panic is the plural of a bank run: when clients run on multiple banks. We call the spread of runs from one bank to others contagion—the same term used to describe the spread of a biological pathogen.

In this primer, we characterize the sources of bank runs and panics, as well as the tools we use to prevent or mitigate them….

Improving resilience: banks and non-bank intermediaries

Debt causes fragility. When banks lack equity funding, even a small adverse shock can put the financial system at risk. Fire sales can undermine the supply of credit to healthy firms, precipitating a decline in economic activity. The failure of key institutions can threaten the payments system. Authorities naturally respond by increasing required levels of equity finance, ensuring that intermediaries can weather severe conditions without damaging others.

Readers of this blog know that we are strong supporters of higher capital requirements: if forced to pick a number, we might choose a leverage ratio requirement in the range of 15% of total exposure (see here), roughly twice recent levels for the largest U.S. banks. But as socially desirable as high levels of equity finance might be, the fact is that they are privately costly. As a result, rather than limit threats to the financial system, higher capital requirements for banks have the potential to shift risky activities beyond the regulatory perimeter into non-bank intermediaries (see, for example here).

Has the increase of capital requirements since the financial crisis pushed risk-taking beyond the regulated banking system? So far, the answer is no. However, in some jurisdictions, especially the United States, the framework for containing systemic risk arising from non-bank financial institutions remains inadequate….

FEMA for Finance

Modern financial systems are inherently vulnerable. The conversion of savings into investment—a basic function of finance—involves substantial risk. Creditors often demand liquid, short-term, low-risk assets; and borrowers typically wish to finance projects that take time to generate their uncertain returns. Intermediaries that bridge this gap—transforming liquidity, maturity and credit between their assets and liabilities—are subject to runs should risk-averse savers come to doubt the market value of their assets.

The modern financial system is vulnerable in a myriad of other ways as well. For example, if hackers were to suddenly render a key identification technology untrustworthy, it could disable the payments system, bringing a broad swath of economic activity to an abrupt halt. Similarly, the financial infrastructure that implements most transactions—ranging from retail payments to the clearing and settlement of securities and derivatives trades—typically relies on a few enormous hubs that are irreplaceable in the short run. Economies of scale and scope mean that such financial market utilities (FMUs) make transactions cheap, but they also concentrate risk: even their temporary disruption could be catastrophic. (One of our worst nightmares is a cyber-attack that disables the computer and power grid on which our financial system and economy are built.)

With these concerns in mind, we welcome our friend Kathryn Judge’s innovative proposal for a financial “Guarantor of Last Resort”—or emergency guarantee authority (EGA)—as a mechanism for containing financial crises. In this post, we discuss the promise and the pitfalls of Judge’s proposal. Our conclusion is that an EGA would be an excellent tool for managing the fallout from dire threats originating outside the financial system—cyber-terrorism or outright war come to mind. In such circumstances, we see an EGA as a complement to existing conventional efforts at enhancing financial system resilience.

However, the potential for the industry to game an EGA, as well as the very real possibility that politicians will see it as a substitute for rigorous capital and liquidity requirements, make us cautious about its broader applicability. At least initially, this leads us to conclude that the bar for invoking an EGA should be set very high—higher than Judge suggests….

Bank Financing: The Disappearance of Interbank Lending

Retail bank runs are mostly a thing of the past. Every jurisdiction with a banking system has some form of deposit insurance, whether explicit or implicit. So, most customers can rest assured that they will be compensated even should their bank fail. But, while small and medium-sized depositors are extremely unlikely to feel the need to run, the same cannot be said for large short-term creditors (whose claims usually exceed the cap on deposit insurance). As we saw in the crisis a decade ago, when they are funded by short-term borrowing, not only are banks (and other intermediaries) vulnerable, the entire financial system becomes fragile.

This belated realization has motivated a large shift in the structure of bank funding since the crisis. Two complementary forces have been at work, one coming from within the institutions and the other from the authorities overseeing the system. This post highlights the biggest of these changes: the spectacular fall in uncollateralized interbank lending and the smaller, but still dramatic, decline in the use of repurchase agreements. The latter—also called repo—amounts to a short-term collateralized loan....

Money Funds -- The Empire Strikes Back?

Shortly after Lehman failed in 2008, investors began to flee from money market mutual funds (MMMFs). To halt the run, the U.S. Treasury guaranteed all $3.8 trillion in outstanding MMMF liabilities. That rescue created enduring moral hazard: the expectation that a future crisis will lead to another bailout.

Aside from their legal form as mutual funds, MMMFs functioned much like banks engaged in the transformation of liquidity, credit and (to some extent) maturity. Similar to banks that redeem deposits at face value, they promised investors a fixed share value of $1 (a “buck”) on demand. Unlike depositories, however, MMMFs had no capital, no deposit insurance, and—at least officially—no access to the lender of last resort. So, when the Reserve Primary Fund “broke the buck” (by failing to redeem at the $1 par value) in September 2008, MMMF investors panicked.

Somewhat surprisingly, it took until 2014 for the Securities and Exchange Commission (SEC) to resolve political conflicts and introduce significant rule changes for MMMFs (see our earlier posts here and here). The SEC now requires that institutional prime MMMFs—which (like Reserve Primary) frequently invest in short-term corporate liabilities—operate like other mutual funds with a floating net asset value (NAV). The same rule applies to institutional municipal MMMFs. Retail MMMFs, as well as those investing in federal government (and agency) securities, are exempt.

In light of a recent legislative proposal to water it down, in this post we review the impact of the SEC’s 2014 reform. To highlight our conclusions: (1) it did not go far enough to reduce run risk; (2) aside from temporary dislocations, it has not raised nonfinancial sector funding costs by more than would be accounted for by reducing the implicit taxpayer guarantee for MMMFs; and (3) reversing the floating-NAV requirement would weaken the safety of the U.S. financial system....

Commentary

Money, Banking, and Financial Markets