The capital conservation buffer is one of the simplest concepts in the prudential framework. It requires banks to hold extra capital above their minimum requirements. The purpose is to ensure that banks build up reserves during normal times that can be drawn down during periods of stress. It creates a cushion that protects the minimums and keeps banks operating when losses occur.
The basic requirement
The buffer is set at 2.5% of risk-weighted assets. It must be met with Common Equity Tier 1 capital. This is the highest quality capital. Ordinary shares and retained earnings. This sits on top of the Pillar 1 minimum of 4.5% CET1, bringing the effective CET1 requirement to 7% before considering other requirements and buffers. Together with the 8% total capital minimum and Pillar 2A, the capital stack builds up to substantial levels.
Unlike minimum capital requirements, the buffer is designed to be used. When a bank faces losses that push it into its buffer, it does not fail or breach a hard regulatory floor. Instead, it faces restrictions on how it can distribute its profits. The buffer is a zone of constrained operation rather than a hard minimum. This is an important distinction.
How the restrictions work
When a bank operates within its buffer rather than above it, capital conservation measures apply. The lower the buffer level, the greater the restrictions. These measures limit dividends to shareholders, bonus payments to staff, and discretionary distributions such as share buybacks. The bank must retain earnings to rebuild capital.
The restrictions operate on a graduated scale. A bank with more than 75% of its buffer intact can distribute up to 60% of its earnings. As the buffer erodes, the maximum distribution percentage falls. A bank with between 50% and 75% of its buffer can distribute up to 40%. Between 25% and 50% allows 20%. A bank with less than 25% of its buffer can distribute nothing until it rebuilds capital. This creates strong incentives to restore the buffer quickly.
This approach ensures that when problems emerge, capital is retained rather than paid out. The buffer absorbs losses while the bank remains fully operational. Shareholders feel the pain through reduced dividends rather than through the bank failing. Management bonuses are constrained rather than being paid regardless of financial performance.
Why this matters
Before the financial crisis, many banks paid dividends and bonuses even as their capital positions deteriorated. Management and shareholders extracted value while the bank weakened. When losses crystallised, there was less capital available to absorb them. Some banks paid dividends in 2007 and 2008 and then required government support shortly afterwards. Taxpayers ended up providing what shareholders had taken out.
The capital conservation buffer addresses this directly. Banks cannot continue rewarding shareholders and executives while their financial position weakens. Capital stays in the bank when it is needed most. The buffer mechanism automates what should have been obvious discipline but was not being exercised.
The buffer also provides flexibility in the framework. Rather than setting minimum requirements so high that any breach triggers severe consequences, regulators created a zone above the minimum where constraints apply but the bank continues operating normally. This is more realistic than pretending banks will never face stress. Banks will sometimes use their buffers. That is what buffers are for.
Implementation
The capital conservation buffer applies to all banks in both the UK and EU. It was phased in between 2016 and 2019 and has been at the full 2.5% level since January 2019. This is a permanent feature of the framework not a transitional measure.
In the UK, responsibility for the capital conservation buffer is transferring from assimilated EU law to PRA rules. HM Treasury made new regulations in 2025 that remove the buffer from statute and give the PRA direct responsibility for setting it. The policy substance remains unchanged at 2.5%. This is part of the broader post-Brexit transfer of financial services regulation from retained EU law to regulator rulebooks.
The buffer forms part of the combined buffer alongside the countercyclical buffer and any applicable systemic buffers. All these buffers share the same characteristic. They can be used in times of stress. Distribution restrictions apply as each buffer layer is eroded. Together they provide substantial loss absorption above the hard minimums.
