In a 43-page research report, the Federal Reserve has authored a rather concerning tome warning that the mechanical positive-feedback rebalancing of Leverage ETFs (LETFs) resembles the portfolio insurance strategies, which contributed to the stock market crash of October 19, 1987. The impact of LETFs on broad stock-market indexes become significant during periods of high volatility (shown empirically in 2008/9 and H2 2011) as they show that LETF rebalancing in response to a large market move could amplify the move and force them to further rebalance which may trigger a “cascade” reaction. Furthermore, executing orders within a short period of time, such as the last hour of trading, may cause disproportionate price changes (especially in financial stocks). The Fed warns that a significant price reduction at market close may also impair investor confidence with accelerating depressed prices at the close potentially driving large investor outflows overnight.
ETF-rebalancing implied price effects are most egregious at times of stress...
ETF rebalancing flows have grown dramatically...
BUT - what is most concerning is that LETF rebalancing flows as a fraction of stock volume in the last hour is surging - especially for small-caps...
The frequency of a large price move in the last hour of trading is zero until 2007 when the first financial LETF is launched. Consistent with the implied price impact results, the frequency of a large price move is elevated when the price volatility is high, reaching 0.8 in the 2008-2009 financial crisis and 0.6 in the second half of 2011. These results, combined with the implied price impact estimates, suggest that LETF rebalancing contributed to the stock market volatility in the 2008-2009 financial crisis and in the second half of 2011.
