Rajiv Sethi Mon 2010-09-20 10:04 EDT

An Extreme Version of a Routine Event

Rajiv

The flash crash of May 6 has generally been viewed as a pathological event, unprecedented in history and unlikely to be repeated in the foreseeable future...far from being a pathological event, the flash crash was simply a very extreme version of a relatively routine occurrence...the flash crash can provide us with insights into the more general dynamics of prices in speculative asset markets...The crash revealed with incredible clarity how (as James Tobin observed a long time ago) markets can satisfy information arbitrage efficiency while failing to satisfy fundamental valuation efficiency...Aside from scale and speed, one major difference between the flash crash and its more routine predecessors was the unprecedented cancellation of trades...this was a mistake: losses from trading provide the only mechanism that currently keeps the proliferation of destabilizing strategies in check...

extreme version; Rajiv Sethi; routine event.

Wed 2010-06-09 18:56 EDT

Rajiv Sethi: The New Market Makers

...the SEC's preliminary report on the flash crash...led me to believe that most of this activity was caused by algorithmic trading strategies placing directional bets based on rapid responses to incoming market data. Two strategies in particular -- momentum ignition and order anticipation -- were explicitly mentioned as potentially destabilizing forces in the SEC's January Concept Release on Equity Market Structure. The SEC invited comments on the release, and dozens of these have been posted to date. There is one in particular, submitted by R.T. Leuchtkafer about three weeks before the crash, that I think is especially informative and analytically compelling...Leuchtkafer traces the history of recent changes in market microstructure and examines the resulting implications for the timing of liquidity demand and supply...The standard argument against increased regulation of the new market makers is that it would interfere with their ability to supply liquidity. Leuchtkafer argues, instead, that the strategies used by these firms cause them to demand liquidity at precisely those moments when liquidity is shortest supply...

New Market Makers; Rajiv Sethi.