Via Chairman Bruce, the US government is getting (more) worried about automated trading in the wake of last week’s largely-unexplained and possibly emergent “stock tornado”; insert aphorism about horses and barn doors here, possibly modified to suggest that the farmer has been letting the horse run the stud for years.

Investment bankers are naturally keen to point out all the benefits of automated trading and “dark pools”:

Goldman Sachs Group Inc., the most profitable firm in Wall Street history, has shared memos with lawmakers and SEC officials that say computer-driven trading and an increase in stock transactions that occur off public exchanges has reduced consumer costs and brought more liquidity to markets.

Well, if we can’t trust Goldman Sachs, who can we trust? #scathingsarcasm