The Bank of England is overhauling its approach to managing the UK's financial plumbing. Governor Andrew Bailey has outlined a framework to continue shrinking the central bank's balance sheet through quantitative tightening while moving to a system where reserve supply is driven by bank demand.
As of early 2026, UK central bank reserves stand at £643.5 billion, down £63.2 billion from March 2025. This decline is significant, but reserves remain well above the BoE's estimated "sweet spot"-the Preferred Minimum Range of Reserves (PMRR).
The PMRR, recently updated, now sits at £365 billion to £515 billion. This range reflects banks' current transactional needs, which are higher than pre-2008 norms to maintain financial stability. The banking system still holds roughly £130 billion more than the top end of this target.
Since 2022, the BoE has reduced its gilt holdings by over £300 billion, leaving about £553 billion on its balance sheet as of December 2025. The central bank is exiting the gilt business to mitigate interest rate risk; when rates rise, bond values fall, generating losses ultimately borne by the UK Treasury.
Operationally, the BoE is adjusting its Short-Term Repo and Indexed Long-Term Repo facilities. These changes aim to let banks draw reserves as needed, rather than operating in a system flooded with excess liquidity.
For markets, the transition introduces uncertainty. Banks accustomed to abundant reserves will need more deliberate liquidity management. The key indicator to watch is how quickly reserves approach the £515 billion PMRR upper bound. At the current pace, this could occur within two years. The true test will be whether the demand-driven model avoids the money market stress that forced the U.S. Federal Reserve to abruptly halt its own quantitative tightening in 2019.