MacroScope

Not everyone agrees that using high-speed machines to trade stocks in less time than it takes the average person to blink is a bad thing, but the people who do might be heartened by the letter a congressman sent the U.S. Securities and Exchange Commission on Friday.

Rep. Edward Markey, a Massachusetts Democrat who has waged a decades-long struggle against computerized trading sent the SEC a hint: The power to curb high-frequency trading has been within its grasp all along.

In his letter, Markey described a law he co-sponsored in 1989 to increase the agency’s power to regulate computerized trading, a precursor to HFT that employed computer programs to make trading decisions without the participation of conscious humans. The law lets the SEC “limit practices which result in extraordinary levels of volatility,” according to Markey’s citation.

Markey, nudging further, added: “If the commission simply makes a finding that the markets are currently in a period of extraordinary market volatility and that HFT is reasonably certain to engender such levels of volatility, the Commission can immediately promulgate rules that restrict or eliminate the practice.”

Do current market conditions warrant this? HFT proponents say high-speed trading reduces volatility in liquid stocks. Volatility in the stock market is the lowest it has been since 2007. But incidents like the May 2010 flash crash, a head-spinning plunge in the stock market precipitated by computers, or the glitch that nearly brought down Knight Capital last summer, could count as their own sort of volatility.

The implosion of MF Global Holdings Ltd, the largest independent U.S. futures broker until it filed for bankruptcy protection on Monday, calls to mind the collapse of Refco – which in its time was the largest independent U.S. futures broker – after revelations that Refco’s CEO had defrauded his investors. (London hedge fund company Man Group Plc bought Refco’s futures brokerage just about six years ago, and later spun off its brokerage and renamed it MF Global.)

But now that questions are arising on the whereabouts of assets that clients entrusted to Jon Corzine’s firm to back their futures trades,  it may also be worthwhile to bear in mind the bankruptcy of another futures brokerage – that of Sentinel Management, in 2007.

Sentinel was a different kind of futures brokerage than MF Global. The company largely managed money for other futures brokers, delivering outsized returns that, Sentinel’s bankruptcy trustee says, were juiced up by improperly using customer money to secure bank loans that went to fund risky trades.  When the credit crisis hit in the summer of 2007, the scheme unraveled, and Sentinel quickly plunged into bankruptcy. Sentinel managed about $2 billion in customer assets; about $600 million of it was never recovered, and clients are still wrangling over how to divvy up what remains.