Part I: One Coordinated Capital Architecture. Here’s What It Actually Means.

On March 19, 2026, the U.S. Federal Reserve published one of the most consequential capital rulemaking packages in a generation. Three Notices of Proposed Rulemaking landed simultaneously — a Basel III risk-based capital NPR for the most internationally active banks, a standardised approach revision for mid-size and smaller institutions, and a G-SIB surcharge NPR that fundamentally re-engineers how systemic risk capital is calculated for the eight largest U.S. firms. Running in parallel are a revised stress testing framework proposed in October 2025 and an enhanced supplementary leverage ratio reset finalised in November 2025 and already effective from April 1, 2026.

Together, these are not four separate workstreams. They form a single, coordinated recalibration of the entire U.S. capital stack — designed to eliminate overlapping requirements, right-size calibrations to match actual risk, and give banks a clearer platform to support economic growth. Vice Chair Bowman named it explicitly: the four pillars.

Most market commentary is focused on whether capital goes up or down. That is the wrong question. The cumulative CET1 impact varies from approximately +13% to −4% across the nine affected Category I and II bank holding companies — a 17-percentage-point spread driven entirely by business model, trading book composition, and funding structure. A firm running a large derivatives franchise faces a materially different outcome than one concentrated in mortgage origination or custody. The headline average of −4.8% tells you almost nothing on its own.

What this series sets out to do

This paper series — authored by Wepoint’s regulatory advisory practice — systematically unpacks each layer of the March 19 architecture and its direct implications for the institutions in scope: the eight U.S. G-SIBs, Category I and II bank holding companies, Category III and IV firms, and smaller banking organisations above $100 billion in assets. Across the series, we trace the four risk stripes — credit, market risk (FRTB), operational risk, and CVA — through the new Expanded Risk-Based Approach; dissect the G-SIB surcharge mechanics including the STWF recalibration and the shift to average-based indicators; examine the cross-jurisdictional divergences between the U.S., EU, and UK frameworks; and identify the specific operating model, pricing, and balance-sheet management changes that each institution type must confront before — not after — the final rule is published.

What Part I delivers

This first instalment provides the foundational strategic frame. It demonstrates why the four pillars must be modelled as one integrated capital architecture, not as four parallel compliance programmes — and why institutions running standalone pillar-by-pillar impact analyses are producing the wrong number.

Key points of the paper:

• The rebalancing underneath the headline. The Basel III NPR alone increases CET1 requirements by 1.4% for G-SIBs, driven by higher market risk and operational risk charges. The offset comes from the G-SIB surcharge NPR (−3.8%) and stress test revisions (−4.3% for market and operational risk components). Capital rises in some places — trading, CVA, operational risk. It falls in others — G-SIB mechanics, leverage, and mortgage/retail lending. The net effect is entirely business-mix dependent.
• Co-calibration is the architecture, not an accident. The Fed’s own Board memo is explicit: the Basel III NPR’s increases in operational and market risk capital were deliberately calibrated to be offset by material reductions in the stress capital buffer for exactly those risk categories. Modelling one without the other overstates the impact by a significant margin. This co-dependence is being missed in nearly every standalone Basel III commentary published to date.
• Four changes that aren’t being talked about enough. The paper unpacks the end of the dual calculation and what the new Expanded Risk-Based Approach replaces it with; why CVA is now explicitly in scope and flows straight into derivatives pricing and P&L; how the G-SIB surcharge is being structurally re-wired, not just reduced; and why AOCI — the SVB lesson written into the rulebook — creates a direct CET1 management question for Category III and IV firms with large AFS portfolios.
• The comment period is the last design lever. Four open questions — CVA scope, AOCI boundaries, mortgage servicing asset risk weights, and STWF calibration — represent genuine opportunities to shape the final rule. The deadline is June 18, 2026. Generic industry letters will not influence the outcome. Specific, data-driven, quantitative submissions will.

The operating model question nobody is asking yet

The paper closes with the argument that capital reform is being run as a compliance programme across the industry — each pillar owned by a different team, all producing output that doesn’t talk to each other. That approach will not work here. What is required is a single integrated capital stack model that runs Basel III RWA, stress capital buffer, G-SIB surcharge, and leverage ratio simultaneously; a binding-constraint analysis that identifies which pillar actually bites for each business line; front-office integration of CVA capital into derivatives and repo pricing; and Treasury recalibration for AOCI treatment that accounts for CET1 volatility, not just P&L volatility.

The institutions that treat this as a capital architecture redesign — not a regulatory compliance exercise — will define the next cycle. This paper shows them where to start.

Fill in the form below to receive the full paper — including the detailed CET1 impact tables by bank category, the business-line capital direction matrix, the integrated modelling framework, and the three near-term actions for CROs, CFOs, and Heads of Capital Strategy.