An exposure limit is a cap on how much a firm can have outstanding with, or stand to lose to, a single counterparty, group, sector, country or activity at any one time. Banks, payment companies, exchanges and clearing houses set such limits so that no single failure causes a loss they cannot absorb. Limits are expressed as an amount of money or as a share of the firm's capital, and they shrink as exposure is used and free up again as positions settle.
Exposure limits are a core tool for managing credit risk and counterparty risk. Some are imposed by regulators, such as the large-exposure rules for banks, and others are set internally to reflect a firm's risk tolerance. In payments they also take the form of settlement limits, net debit caps and caps on how much a partner can be prefunded or owed.
Exposure limit in plain terms
A shopkeeper who lets regular customers buy on credit usually keeps a tab for each one and refuses more credit once the tab reaches a set amount. When the customer pays, the tab drops and they can buy on credit again. The cap means that even if one customer disappears without paying, the shop survives.
An exposure limit is that tab, applied by banks and payment firms to the businesses they deal with. It does not say whether a partner is trustworthy; it says how much the firm is prepared to lose if that partner turns out not to be.
Regulatory large-exposure limits
The Basel Committee on Banking Supervision published its large-exposures framework in April 2014, and it took effect from 1 January 2019 as part of the Basel III reforms. Under it, a bank's exposure to a single counterparty or a group of connected counterparties may not exceed 25% of its Tier 1 capital, with a tighter 15% limit between global systemically important banks. Exposures of 10% or more of Tier 1 capital must be reported to supervisors. Each jurisdiction applies the standard through its own law, for example the European Union's Capital Requirements Regulation.
These rules exist because concentration has repeatedly turned one firm's failure into another's: heavy losses to a single borrower or bank were a recurring feature of past banking crises.
Exposure limits in payments and settlement
Payment and settlement systems use limits to contain settlement risk:
- Net debit caps. The Federal Reserve's Payment System Risk policy caps how far a bank's account can be overdrawn during the day, including through Fedwire payments, which controls the intraday credit the central bank extends.
- Short position limits. CLS, which settles foreign-exchange trades on a payment-versus-payment basis to reduce Herstatt risk, limits how negative each member's position may become in each currency.
- Clearing member limits. A central counterparty sets position and credit limits for its members and backs them with initial margin and other collateral.
- Merchant and partner limits. An acquirer limits how much card volume a merchant can process before funds are held in reserve, and remittance companies limit how much they prefund to, or are owed by, each payout partner.
How limits are set and used
A limit is usually based on the counterparty's financial strength, the collateral it posts, the type of exposure and the firm's own capital. Exposure is commonly measured as the amount at risk if the counterparty failed today, sometimes with an add-on for how that amount could grow. Usage is tracked continuously: each new deal reduces available headroom and each settled deal restores it.
A simple example shows the cycle. A provider posts $5,000 of collateral, and its partner allows 80% of that to be used, giving a limit of $4,000. After accepting a $1,000 payment, the provider has $3,000 of headroom until that payment settles, at which point the full $4,000 is available again. Because headroom recycles, the speed of settlement matters as much as the size of the limit. This is a central argument in designs such as the tradable remittance contract, where an exchange would check each provider's remaining limit before its matching engine considers an offer, and in efforts to cut idle liquidity.
Limitations
Limits work only if exposures are measured correctly. Hidden links between counterparties, wrong-way risk (where exposure rises just as the counterparty weakens) and sudden market moves can make a limit far less protective than it looks. Limits can also be overrun in practice when systems lag, or when netting arrangements fail to hold up in an insolvency. Tight limits reduce risk but also reduce business, and blanket cuts across a whole sector can amount to de-risking that shuts out customers who pose little real danger. Supervisors therefore expect limits to sit within a wider framework of monitoring, collateral, escalation when a limit is breached and control of operational risk.