In their Q2 letter to clients, Jeff Silver and Ben Hunt of Iridian Asset Management provide an update of the fund's performance and some notable holdings (long: TOO; short: TXT) but the core of the letter is the recap of the firm's "Hollow Market" theme, this time refocusing on what we have long claimed is the biggest threat to market integrity, High Frequency Trading: "On May 6th we saw the hollow market revealed via the so-called “flash crash”, where liquidity throughout US equity markets vanished in the time it takes to turn off a computer server running a high-frequency trading algorithm. As we wrote to our investors that afternoon, we believe that it was the interaction of trading algorithms, ETF’s, and decentralized venues that created the flash crash." The firm proceeds to highlight the two outcomes of what is now known as the Hollow Market paradigm: i) a constant, non-trivial chance of severe market dislocation (which includes a reference to the seminal paper Is High-Frequency Trading Inducing Changes in Market Microstructure and Dynamics, first posted with comments on Zero Hedge, and ii) the need for a Tobin tax, another topic long endorsed by Zero Hedge as a means of fixing the market. Furthermore, all those still confused by Zero Hedge's fascination with VWAP strategies, can finally sleep well after reading this letter. All in all, a must read analysis for everyone (and even the two employees at the SEC with an IQ greater than single digits), curious as to how screwed up our current market truly is (also, thanks for the shout-out).