From the Key Takeaways: " Amid widespread sell-offs in risky asset classes, corporate bond exchange-traded funds (ETFs) traded at steep discounts to underlying asset values in March.  Contributing factors were high market volatility, reduced risk-taking by dealers and investors' reaction to policy decisions.  Policy interventions that improve market functioning in a given sector can have temporary yet important spillovers to other segments through portfolio rebalancing by investors."
BIS Bulletin No. 6; Bank for International Settlements No. 6
2020 Bank for International Settlements
Bank for International Settlements: https://www.bis.org/