The development of electronic and automated trading in sovereign bond markets has been accompanied by a more frequent occurrence of flash crashes, i.e., episodes of sudden and abrupt price changes that are to a large extent reversed shortly afterwards.
In a recent working paper from the European Securities and Markets Authority (ESMA), researchers analyzed two flash events in the German and Italian bond markets and show how liquidity vanished ahead of the crashes, resulting in trades having a large price impact on prices.
They document that, during the flash event of 29 May 2018, activity on Italian bonds futures and cash markets diverged: trading activity in futures surged, while it plummeted on the cash market. In addition, they show that the effects of flash events on the liquidity in the affected markets can last up to several weeks.
The findings call for increased monitoring of electronic trading markets, taking into account the pace of financial innovation, and for pursuing more integrated approaches in the presence of highly interlinked markets.