In this paper, we provide an overview of the concerns surrounding the variations in the calculation of risk-weighted assets (RWAs) across banks and jurisdictions and how this might undermine the Basel III capital adequacy framework. We discuss the key drivers behind the differences in these calculations, drawing upon a sample of systemically important banks from Europe, North America, and Asia Pacific. We then discuss a range of policy options that could be explored to fix the actual and perceived problems with RWAs, and improve the use of risk-sensitive capital ratios. Strengthening capital ratios is a key priority in the aftermath of the global financial crisis. Increasing the quantity, quality, and transparency of capital is of paramount importance to restore the banking sector to health. Recent regulatory reforms have primarily focused on improving the numerator of capital ratios, while changes to the denominator, i.e., risk weighted assets (RWAs), have been more limited.

Why look at RWAs now? Confidence in reported RWAs is ebbing. Market participants question the reliability and comparability of capital ratios, and contend that banks may not be as strong as they are portrayed by risk-based capital ratios. The Basel Committee recently announced it will review the measurement of RWAs and formulate policy responses to foster greater consistency across banks and jurisdictions. The academic literature on capital is vast, but the focus on RWAs is more limited. Current studies mostly emanate from market participants, who highlight the wide variations existing in RWAs across banks. There is no convergence in views about the materiality and relative importance of these differences, and thus no consensus on policy implications. This paper aims to shed light on the scale of the RWA variation issue and identify possible policy responses. The paper (i) discusses the importance of RWAs in the regulatory capital framework; (ii) highlights the main concerns and the controversy surrounding RWA calculations; (iii) identifies key drivers behind the differences in RWA calculations across jurisdictions and business models; and (iv) concludes with a discussion on the range of options that could be considered to restore confidence in banks’ RWA numbers. A comprehensive analysis of broader questions, such as what is the best way to measure risk or predict losses, and what is the optimal amount of capital that banks should hold per unit of risk, is beyond the scope of this study. A comparison of the respective merits of the leverage and risk-based capital ratios is also outside our discussion.