Fed’s unconventional monetary policy and risk spillover in the US financial markets

This study examines volatility spillover dynamics among the S&P 500 index, the US 10-year Treasury yield, the US dollar index futures, and the commodity price index. The focus of the study is to analyze the effects of the Fed’s unconventional monetary policy on the US financial markets. We use realized volatility measures based on daily data covering the period from December 29, 1996, to November 12, 2018. To address nonlinear and asymmetric spillover dynamics in low and high volatility states, we propose a new regime-dependent spillover index based on a smooth transition vector autoregressive (STVAR) model, extending the study of Diebold and Yilmaz (2008, 2012) to regime switching models. When applied to US financial data, we find strong evidence that the US financial market risk structure changes after the 2008 Global Financial Crisis and announcement of quantitative easing (QE) programmes through the portfolio balance channel. The risk spillover moves from purchased assets to non-purchased assets after the QE announcements.