Institutional participation in digital asset custody is currently paralyzed by a deliberate, multi-agency regulatory gridlock. The foundational scaffolding of traditional safekeeping has been replaced by an architecture of exclusion, driven primarily by conflicting accounting and capital requirement paradigms.
This forensic report deconstructs the mathematical and legal reality of this custody chokepoint. We isolate the exact balance sheet liabilities imposed by SAB 121 and model the devastating Supplementary Leverage Ratio (SLR) inflation triggered by the Basel III Endgame's 1250% risk weight mandate for Group 2 assets.
The mandate comprehensively maps the resulting structural shift: the enforced migration of institutional capital into an oligopoly of state-chartered and OCC national trusts. We dissect the 2026 OCC chartering amendments and the profound legal friction generated by the SEC's Safeguarding Rule, defining the exact perimeter of fiduciary survival.