The Bank of International Settlements may limit the way banks measure their risk-weighted assets for capital requirements, as it seeks to deal with the problem of risk-weighted asset variability.The chairman of the BIS's Basel Committee on Banking Supervision, Stefan Ingves, said this variability was a "key problem" that needed to be fixed.In a speech earlier this week, Ingves said: "People are asking if we can rely on the risk-weighted asset measurements that stand at the Basel framework's core.""Our studies show that actual risks drive the lion's share of differences in risk weights and capital requirements. This is just as it ought to be."But variations also arise from supervisory and bank-practice idiosyncrasies, and these can result in material discrepancies. The range of bank practice-based variations is uncomfortably wide."Two banks with exactly the same assets could report capital ratios that differ by four percentage points. That is, if the most conservative bank reported a regulatory capital ratio of eight per cent, the least conservative would report 12 per cent."The potential for difference this wide weakens confidence in the measurement of bank capital."The committee is considering a set of "simplifications and safeguards" that would help limit variability but still provide for appropriate risk sensitivity in risk-weighted asset measures.Ingves said that one way to limit variability was to constrain banks' modelling choices and assumptions"We are also looking at the role of floors and benchmarks within the Basel III framework, particularly for products and markets where data are limited," he said.The committee is also looking at the issue of national discretions. This involves an evaluation of whether more can be done to reduce variability by eliminating discretions where possible and strengthening supervisory guidance.And on the disclosure front, the committee plans to mandate improvements to the information that banks provide on their risk profiles. It is conducting a review of Pillar 3 disclosure requirements, with a particular focus on compatibility across banks.