重新审视监管资本堆栈

November 2025 FSI Briefs are written by staff members of the Financial Stability Institute (FSI) of the Bank for InternationalSettlements (BIS), sometimes in cooperation with other experts. They are short notes on regulatory andsupervisory subjects of topical interest and are technical in character. The views expressed in this This publication is available on the BIS website (www.bis.org). To contact the BIS Global Media and PublicRelationsteam,pleaseemailmedia@bis.org.Youcansignupforemailalertsat Revisiting the regulatory capital stack Highlights •The post-Great Financial Crisis regulatory reforms have directly contributed to a more resilientfinancial system and supported sustainable growth, but some concrete aspects can be improved.•The complexity of the current capital framework and limitations in the loss-absorbing capacity ofsomeof its components can limit the effectiveness of bank regulation in achieving coremicroprudential, macroprudential and resolution objectives. 1.Introduction The capital stack is the bedrock of banking regulation, serving multiple policy objectives. From amicroprudential perspective, it seeks to safeguard the safety and soundness of individual banks. From amacroprudential standpoint, it strengthens the resilience of the financial system, moderates the amplitudeof the financial cycle and helps to reduce the likelihood that shocks propagate. In addition, parts of thecapital stack absorb losses to facilitate the orderly resolution of failing banks. Since the Great Financial Crisis (GFC), the capital – as well as liquidity – positions of banks haveimproved significantly, and the banking sector’s enhanced resilience has supported sustainable economicgrowth. The aftermath of the Covid-19 crisis is a testament to banks’ resilience. In contrast to 2008, whenbanks were the source of vulnerabilities, the Basel III reform underpinned their role as a shock absorber That said, a debate has emerged on possible ways to improve the current design of the regulatorycapital stack. While the available evidence does not suggest that this is an urgent task, there appears to For one, the multifaceted nature of the capital stack introduces undesirable complexity. Banksmust comply with several interlocking requirements, including those for Common Equity Tier 1 (CET1)capital, Tier 1 capital, total capital, various regulatory buffers, total loss-absorbing capacity (TLAC) and the 1RodrigoCoelho(rodrigo.coelho@bis.org),NikolaTarashev(nikola.tarashev@bis.org)andFernandoRestoy(fernando.restoy@bis.org), Bank for International Settlements (BIS); Claudio Borio (borio.cev@outlook.com), formerly at BIS.The authors are grateful to Wayne Byres, Renzo Corrias, Andrea Enria, Gaston Gelos, Ruth Walters and Sam Woods for theirhelpful comments and to Claire Rowley for administrative support. difficult, and even just calculating them can become burdensome. The complexity thus creates challengesnot only for banks but also for investors, observers and even supervisors, potentially undermining the Moreover, and in part because of its complexity, the framework faces challenges in delivering onits core purpose of loss absorption. Notably, while a bank needs to meet several minimum requirementsto be considered viable, instruments eligible for some of these requirements need not improve the bank’sviability. Conversely, instruments that do underpin viability can also meet requirements for resolution,introducing possible inconsistencies in the framework. Further, while CET1 capital has been highly effective These limitations raise questions about the current design of the capital stack. To what extent isit helping the regulatory framework to achieve its diverse objectives? Could these be met in a more This paper seeks to contribute to this important debate. Based on an evaluation of the currentcapital stack, it analyses how to strike a better balance between functionality and simplicity. Importantly, While the evaluation is broad, some important regulatory aspects are out of scope. First, theanalysis does not cover in any depth jurisdiction-specific arrangements (eg as laid out in Pillar 2 of Basel III).Thefocus is on international standards and common elements across jurisdictions.Second,byconcentrating on requirements in terms of risk-weighted ratios, the analysis leaves the leverage ratio inthe background. It takes it for granted that it is appropriate to rely on a leverage ratio as a backstop to thelimitations of risk weights. Third, the paper does not cover coordination issues among authorities – ie The rest of the paper proceeds as follows. Section 2 offers a general analytical framework thatlays out the objectives of the capital stack and maps the functions of its components to various conditions 2.The capital stack: policy objectives and functions across states The capital stack and its various components serve three interconnected objectives. When a bank remainsa going concern, the components of the sta