Felix Salmon

The HFT debate

April 1, 2014

CNBC might be guilty of a tiny bit of hyperbole when they say that their HFT debate today, between the CEOs of rival exchanges IEX and BATS, “stopped trading on the floor of the New York Stock Exchange” and “Twitter stopped too”. Still, they undoubtedly caused a lot of buzz, and the debate — coming, as it does, in the wake of the release of Michael Lewis’s new book on the subject — is an extremely important one, and it is indeed of great interest to that most endangered of species, the NYSE floor trader.

Michael Lewis’s flawed new book

March 31, 2014

I’m halfway through the new Michael Lewis book — the one that has been turned into not only a breathless 60 Minutes segment but also a long excerpt in the New York Times Magazine. Like all Michael Lewis books, it’s written with great clarity and fluency: you’re not going to have any trouble turning the pages. And, like all Michael Lewis books, it’s at heart a narrative about a person — in this case, Brad Katsuyama, the founder of a small new stock exchange called IEX.

The SEC’s important case against Stevie Cohen

July 21, 2013

Stevie Cohen is one of the greatest stock-market traders of all time. Indeed, there’s a strong case to be made that he’s the greatest. Cohen is not the greatest investor — he doesn’t really go in for buy-and-hold positions which steadily accumulate enormous value over decades. He’s not even the greatest hedge-fund manager: he doesn’t go in for the big macro bets (Soros vs. the pound, Paulson vs. mortgage-backed securities) which are the stuff of legend. Instead, he’s a trader, and while normal people pretty much understand what someone like Warren Buffett does, or what someone like John Paulson does, it’s much harder to understand what a trader does, or what differentiates a good trader from a bad trader.

Why there’s less high-frequency trading

October 15, 2012

Nathaniel Popper arrives today with something that looks like good news on the high-frequency trading front: there’s less of it!

HFT charts of the day, trading-cost edition

August 14, 2012

14speed-articleInline.jpg The Nanex HFT chart I posted last week went viral, becoming by far my most popular post of the year; I even did a version of it for Buzzfeed. In the comments to that post, Kid Dynamite defended high-frequency trading by saying that spreads have tightened in substantially for everyone as a result of HFT. But neither of us really had the numbers — until now.

Dennis Kelleher, Libor, and high-frequency trading

August 8, 2012

Dennis Kelleher of Better Markets has responded to my post in which I said, inter alia, that he was wrong about high-frequency trading. He, of course, says that I’m wrong — indeed, that I’m “over the top and just plain wrong in many ways”, and that the post is “self-discrediting”. Blogfight! So, fair warning: this post is my response to his response to my post; if you’re not into that kind of thing I fully understand, and you’re probably much more grown-up than either of us. Anyway.

Small investors vs high-speed traders

August 7, 2012

One of the problems with financial journalism is its rather kludgy attempts to appeal to a general audience. If something bad happens, for instance, it has to be presented as being bad for the little guy. This was a huge problem with the Libor scandal, since anybody with a mortgage or other loan tied to Libor ended up saving money as a result of it being marked too low.

Chart of the day, HFT edition

August 6, 2012


This astonishing GIF comes from Nanex, and shows the amount of high-frequency trading in the stock market from January 2007 to January 2012. (Which means that the Knightmare craziness of last week is not included.)

When large-scale complex IT systems break

August 1, 2012

It’s rogue algo day in the markets today, which sounds rather as though the plot to The Fear Index has just become real, especially since the firm at the center of it all is called The Dark Knight, or something like that. At heart, however, is something entirely unsurprising: weird things happen when you get deep into the weeds of high-frequency trading, a highly-complex system which breaks in entirely unpredictable ways.