G-SIB capital buffer fails to curb bank risk-taking
A Bank of Russia study reveals global systemically important banks (G-SIBs) react asymmetrically to Basel III capital buffer adjustments. Banks tend to reduce capital ratios and expand lending when buffers are lowered, but do not increase capital ratios or reduce lending when buffers are raised, leading to increased risk-taking.
Banks' asymmetric capital dance
The study, conducted by Heinrich Penikas of the Bank of Russia, analyzed the behavior of global systemically important banks (G-SIBs) over 12 years of Basel III capital buffer adjustments.
It found a significant asymmetric reaction: when the applicable capital buffer is officially lowered by regulators, banks tend to reduce their capital adequacy ratios and expand lending.
Conversely, when the buffer is officially raised, banks do not proportionally increase their capital adequacy ratios or reduce lending.
Instead, they utilize previously accumulated capital reserves to absorb the stricter prudential requirements.
This behavior suggests that the regulation, rather than consistently fostering stability, inadvertently incentivizes global banks to take on more risks, especially when regulatory requirements are tightened.
The research recommends less frequent revisions of the G-SIB list and capital surcharges to mitigate these unintended reactions.
Basel's G-SIB conundrum
The effectiveness of Basel III's capital buffer for global systemically important banks (G-SIBs) has faced renewed scrutiny, especially after the 2023 collapse of Credit Suisse.
This buffer, designed to mitigate systemic risks from 'too big to fail' institutions, is annually reviewed and adjusted by the Financial Stability Board (FSB).
The study employed a modified difference-in-differences (DiD) methodology, adapted for multi-period impacts and changing bank groups.
This approach allowed researchers to robustly assess how G-SIBs respond to these regulatory changes, specifically testing for a symmetric and proportional reaction to capital requirement adjustments.
Unintended consequences persist
This research highlights a critical, often overlooked, flaw in the design and implementation of G-SIB capital regulation.
The asymmetric response suggests banks strategically manage their capital, potentially undermining the prudential goals of the buffer.
Regulators must re-evaluate the frequency and impact of buffer adjustments to genuinely enhance financial stability.