This book is seeming to prompt outrage, although it is not clear exactly why. The basic story of high frequency trading is not new. It has been reported in most major news outlets over the last few years. It would be nice if we could move beyond the outrage to a serious discussion of the policy issues and ideally some simple and reasonable policy to address the issue. (Yes, simple should be front and center. If it's complicated we will be employing people in pointless exercises -- perhaps a good job program, but bad from the standpoint of effective policy.)

The issue here is that people are earning large amounts of money by using sophisticated computers to beat the market. This is effectively a form of insider trading. Pure insider trading, for example trading based on the CEO giving advance knowledge of better than expected profits, is illegal. The reason is that it rewards people for doing nothing productive at the expense of honest investors.

On the other hand, there are people who make large amounts of money by doing good research to get ahead of the market. For example, many analysts may carefully study weather patterns to get an estimate of the size of the wheat crop and then either buy or sell wheat based on what they have learned about the about this year's crop relative to the generally held view. In principle, we can view the rewards for this activity as being warranted since they are effectively providing information to the market with the their trades. If they recognize an abundant wheat crop will lead to lower prices, their sales of wheat will cause the price to fall before it would otherwise, thereby allowing the markets to adjust more quickly. The gains to the economy may not in all cases be equal to the private gains to these traders, but at least they are providing some service.

By contrast, the front-running high speed trader, like the inside trader, is providing no information to the market. They are causing the price of stocks to adjust milliseconds more quickly than would otherwise be the case. It is implausible that this can provide any benefit to the economy. This is simply siphoning off money at the expense of other actors in the market.

There are many complicated ways to try to address this problem, but there is one simple method that would virtually destroy the practice. A modest tax on financial transactions would make this sort of rapid trading unprofitable since it depends on extremely small margins. A bill proposed by Senator Tom Harkin and Representative Peter DeFazio would impose a 0.03 percent tax on all trades of stocks, bonds, and derivatives. This would quickly wipe out the high-frequency trading industry while having a trivial impact on normal investors. (Most research indicates that other investors will reduce their trading roughly in proportion to the increase in the cost per trade, leaving their total trading costs unchanged.)The Joint Tax Committee projected that this tax would raise roughly $400 billion over a decade.

A scaled tax that imposed a somewhat higher fee on stock trades and lower fee on short-term assets like options could be even more effective. Japan had a such tax in place in the 1980s and early 1990s. It raised more than 1 percent of GDP ($170 billion a year in the United States). Representative Keith Ellison has proposed this sort of tax for the United States.