These are interesting times for thinking about securities litigation claims. With Halliburton now decided, the securities bar can move past all the sturm und drang that preceded its issuance. Meanwhile, litigation over high speed trading and dark pools provides an interesting lens for thinking about the ruling. For at least a couple of years, high speed trading and dark pools have been controversial topics. Then came the Flash Boys book by Michael Lewis, and renewed attention and focus, including comments from senior officials at the SEC. This week, the New York AG has sued Barclays regarding alleged fraud in the operation of its dark pools, and Barclays quickly lost billions of share value. According to a June 26, 2014 Financial Times article, the lawsuit was followed by $13 billion of share prices losses for owners of dark pools.

Do we have efficient markets, or not, in terms of processing information and applying it to share prices? What is efficiency? Where does prior knowledge fit in? Does it become controlling that some lawyers took the step of filing suit over information previously known or rumored on the web?