International Banking Regulations: Basel III, AML, and Sanctions

International banking regulations are the shared rules that govern how banks operating across borders hold capital, manage liquidity, prevent financial crime, and comply with sanctions. They come from a handful of international bodies, most importantly the Basel Committee on Banking Supervision and the Financial Action Task Force, and none of them are binding law on their own. Each country decides how, and when, to write them into domestic rules. The most visible piece is the Basel framework, which requires banks to hold Common Equity Tier 1 capital of at least 4.5% of risk-weighted assets, with additional buffers that can push the effective requirement past 10% for large institutions.¹

What Basel III Requires Banks to Hold

Basel III is the current version of the global capital rulebook, rewritten after the 2008 crisis exposed banks that looked well-capitalized on paper but held too little genuine loss-absorbing equity. It tightened both the amount and the quality of capital banks must carry and added new requirements for liquidity and leverage that earlier versions ignored.

Capital Ratios

Basel III sets three minimum capital ratios, each measured against risk-weighted assets. Risk weighting assigns different values to different exposures: a government bond might carry a low weight, while an unsecured corporate loan carries a higher one, reflecting a greater risk of default.²

Common Equity Tier 1, the highest-quality capital such as retained earnings and common shares, must be at least 4.5% of risk-weighted assets.
Tier 1 capital, which adds certain instruments that absorb losses while the bank keeps operating, must be at least 6%.
Total capital, adding Tier 2 instruments like subordinated debt that absorb losses if the bank fails, must be at least 8%.¹

These are floors. Buffers layered on top push the real requirement much higher. The Capital Conservation Buffer adds 2.5% of CET1, and a bank that dips into it faces escalating restrictions on dividends, share buybacks, and discretionary bonuses until capital is rebuilt.³ The Countercyclical Capital Buffer, set nationally, can add up to another 2.5% and is designed to force banks to build extra capital during credit booms so they have a cushion when conditions reverse.⁴ Banks designated as Global Systemically Important Banks face a further surcharge of 1% to 3.5%, depending on their size, interconnectedness, and complexity.⁵ For the largest global banks, all these layers combined can push the effective CET1 requirement past 13%.

Leverage and Liquidity

Risk-weighted ratios rely on models, and models can underestimate risk. Basel III adds a minimum leverage ratio of 3%, calculated as Tier 1 capital divided by total exposure with no risk weighting, as a backstop against banks becoming dangerously overleveraged even when their models say otherwise.⁶

Two liquidity standards address the other lesson from 2008, that a bank can meet capital rules and still run out of cash. The Liquidity Coverage Ratio requires banks to hold enough high-quality liquid assets to cover expected net cash outflows over a 30-day stress period, at a minimum ratio of 100%.² The Net Stable Funding Ratio takes a longer view, requiring stable funding sources to match or exceed longer-term lending and investment activities, also at a minimum of 100%. This discourages funding long-term loans with short-term wholesale borrowing, the maturity mismatch that brought down several institutions during the crisis.

Supervision and Disclosure

The framework has three pillars. Pillar 1 is the minimums above. Pillar 2 gives national supervisors authority to look at each bank’s specific risk profile and demand additional capital if they find weaknesses; a bank with heavy exposure to one industry can be told to hold more even if its headline ratios look healthy.² Pillar 3 requires banks to publicly disclose their risk exposures, capital structure, and risk management practices, on the theory that informed investors and counterparties will impose their own discipline.

Separately, the Financial Stability Board’s Total Loss-Absorbing Capacity standard requires Global Systemically Important Banks to hold at least 18% of risk-weighted assets in instruments that can absorb losses or convert to equity if the bank reaches the point of failure, so that failure is paid for by investors and creditors rather than taxpayers.⁷

Rules Against Money Laundering and Terrorist Financing

A separate body of international standards targets financial crime rather than solvency. The Financial Action Task Force publishes 40 Recommendations that form the global framework for combating money laundering, terrorist financing, and the financing of weapons proliferation.⁸ They rest on a risk-based approach: countries and banks are expected to identify where their greatest exposure to illicit finance lies and concentrate resources there.

Operationally, banks must verify who their customers are, understand the nature of their business, and monitor transactions for signs of criminal activity. This Customer Due Diligence process runs from basic identity verification for ordinary retail accounts up to Enhanced Due Diligence for higher-risk relationships, including politically exposed persons and clients from jurisdictions with weak anti-money laundering controls.⁹ When a bank identifies transactions or behavior that suggest potential criminal activity, it must file a report with the relevant government financial intelligence unit. Institutions face substantial monetary penalties for non-compliance, and individuals involved in willful failures to report can face criminal liability.

Enforcement runs through peer reviews called mutual evaluations, where teams from member countries assess another country’s anti-money laundering framework, examining both whether the laws meet the technical requirements and whether they are actually working.¹⁰ Countries that fail to address identified weaknesses can be placed on the FATF’s list of jurisdictions under increased monitoring, commonly known as the grey list.¹¹ Banks worldwide treat transactions involving grey-listed countries with greater caution, which increases costs and delays cross-border payments for businesses in those jurisdictions.

Sanctions Screening

Banks operating internationally also have to navigate economic sanctions imposed by individual countries and international bodies. Sanctions programs restrict or prohibit financial transactions with designated individuals, entities, and sometimes entire countries, and banks bear primary responsibility for screening transactions and blocking assets when required.

One technical wrinkle worth flagging, because it catches banks off guard: under the approach used by several major jurisdictions, an entity owned 50% or more by one or more sanctioned parties is itself treated as blocked, even if it does not appear on any sanctions list by name. The threshold applies to both direct and indirect ownership, and stakes held by multiple sanctioned parties are aggregated. In most frameworks the rule applies to ownership, not control, so an entity controlled but not majority-owned by a sanctioned person is not automatically blocked.¹² Banks have to trace ownership chains through multiple layers of corporate structure, which makes compliance resource-intensive.

Newer Areas: Crypto and Climate

The international framework is expanding into two areas that barely registered a decade ago. The Basel Committee finalized its prudential standard for banks’ crypto-asset exposures, with implementation set for January 2026. The framework classifies crypto assets into groups that determine how much capital banks must hold against them; stablecoins meeting specific criteria around reserve backing and redemption rights qualify for a preferential treatment with lower capital charges, while unbacked cryptocurrencies face much steeper requirements.¹³

On climate, the International Sustainability Standards Board published IFRS S2, which requires companies including banks to disclose climate-related physical and transition risks, scenario analyses, and greenhouse gas emissions. For banks specifically, IFRS S2 requires disclosure of “financed emissions,” the greenhouse gas output associated with their lending and investment portfolios, broken down by industry and asset class.¹⁴ Adoption varies: some jurisdictions have built the standards into their regulatory frameworks, others are still evaluating how.

Who Actually Writes These Rules

No single global regulator has the power to write enforceable banking law. A network of international bodies develops standards through consensus, and each country decides how to adopt them into domestic law.

The Basel Committee on Banking Supervision is the primary standard-setter for prudential regulation. Its members are banking supervisors and central banks from major economies, and it produces the Basel Accords and monitors their implementation through the Regulatory Consistency Assessment Programme.¹⁵ The Financial Stability Board coordinates national authorities and standard-setting bodies, identifies systemic vulnerabilities, and monitors whether countries are actually implementing what they agreed to.¹⁶ The FATF sets the global standards on money laundering and terrorist financing and enforces them through mutual evaluations and the grey list.⁸ The Bank for International Settlements in Basel hosts most of the prudential standard-setting bodies and provides the venue where central bankers and supervisors coordinate.¹⁷ The Committee on Payments and Market Infrastructures, also hosted at the BIS, sets standards for payment, clearing, and settlement systems.¹⁸

Why the Rules Don’t Land Evenly Across Countries

Every international standard described above is technically a recommendation. None carry the force of law until a country’s legislature or regulators formally adopt them, and the pace varies widely.

As of late 2025, only 8 of the 20 Basel Committee member jurisdictions had fully implemented the final Basel III reforms. Several major economies, including the United States and the United Kingdom, had not yet implemented any portion of the revised standards. The European Union began applying most of its implementing rules in January 2025, with remaining provisions phasing in through 2027. The United States is still working on its revised proposal, with final adoption anticipated in 2026 and a phase-in period extending to 2028. The United Kingdom delayed its implementation to January 2027, with internal models for market risk potentially pushed to 2028.¹⁹

When major jurisdictions move at different speeds, it creates opportunities for regulatory arbitrage, where banks shift activities toward whichever jurisdiction has less demanding rules. The BCBS tracks this through its Regulatory Consistency Assessment Programme, which publishes detailed assessments comparing each country’s domestic rules against the Basel framework.²⁰ The FATF’s mutual evaluations and grey-listing create similar reputational pressure on the anti-money laundering side. The gap between agreed international standards and on-the-ground implementation is the weakest link in the global regulatory architecture, and it is the reason a bank subject to “international” rules can still look very different depending on where it is headquartered.

1
Bank for International Settlements. Definition of Capital in Basel III – Executive Summary
2
Bank for International Settlements. Basel Framework – Standardised Approach: Individual Exposures
3
Bank for International Settlements. Basel Framework – RBC30 Buffers Above the Regulatory Minimum
4
Bank for International Settlements. Countercyclical Capital Buffer (CCyB)
5
Bank for International Settlements. G-SIB Framework: Cut-off Score and Bucket Thresholds
6
Bank for International Settlements. Basel III Leverage Ratio Framework – Executive Summary
7
Bank for International Settlements. TLAC – Executive Summary
8
Financial Action Task Force. FATF Recommendations
9
Financial Action Task Force. International Standards on Combating Money Laundering and the Financing of Terrorism and Proliferation
10
Financial Action Task Force. Mutual Evaluations
11
Financial Action Task Force. Black and Grey Lists
12
U.S. Department of the Treasury. Entities Owned by Blocked Persons (50 Percent Rule)
13
Bank for International Settlements. Basel Committee Publishes Final Disclosure Framework for Cryptoasset Exposures
14
IFRS Foundation. IFRS S2 Climate-related Disclosures
15
Bank for International Settlements. Basel Committee Charter
16
Financial Stability Board. About the FSB
17
Bank for International Settlements. About BIS
18
Bank for International Settlements. Committee on Payments and Market Infrastructures – Overview
19
European Parliament. The Implementation of Basel III: Progress, Divergence and Policy
20
Bank for International Settlements. Regulatory Consistency Assessment Programme (RCAP) – Handbook for Jurisdictional Assessments