By James Kwak

One of the criticism’s of Michael Lewis’s book is that he gets his moral wrong. High-frequency trading doesn’t hurt the little guy, as Lewis claims; instead, it hurts the big guy. The explanation is this: people sitting at their desks buying 100 shares of Apple are getting the current ask, so mainly they care about volume and tight bid-ask spreads. Institutional investors, buy contrast, want to buy and sell huge blocks of shares, and they don’t want the price to move in the process; they are the ones being front-run by the HFTs. Felix Salmon pointed this out, and it’s the subject of an op-ed by Philip Delves Broughton today.

What this leaves out is the question of who ends up being harmed. To figure that out, you have to ask whose money we’re talking about when we say “institutional investor.” If it’s SAC Capital, meaning Steven Cohen’s money, then who cares? But most ordinary people invest—if they are lucky enough to have money to invest—through mutual funds (401(k) plans, for example, are largely invested in mutual funds), and those funds are among the “institutional investors” losing money to HFTs. Another big chunk of institutional money belongs to pension funds. In this case, if the pension fund does poorly, the money may come out of its corporate sponsor in the form of increased contributions—or it may come out of beneficiaries and taxpayers in the form of a bankrupt plan shifting its obligations to the PBGC. Then there are insurance companies: in that case, losses from trading affect shareholders, but if they are systemic across the industry they end up as higher premiums for consumers.

This is not to say that the institutional investors are warm and cuddly and are just passive victims in all of this. I’ve spilled enough ink inveighing against active asset managers, and Salmon points out that the buy side bears its share of blame for being careless with other people’s money. At the end of the day, if HFT harms other people in the markets, it’s just a fraternal spat among capital, and doesn’t affect the fundamental divide in the post-Piketty world. Until a poorly-tested algorithm goes berserk and freezes the financial system, that is.