This article was originally distributed by the McClatchy-Tribune News Service.

Remember the May 6 stock market “flash crash,” when the Dow plummeted nearly 1,000 points in less than an hour? The experts are still scratching their heads over the exact cause of that historic market bungee jump.

What is clear is the plunge never would have happened without automated high-frequency trading, which accounts for 50 percent to 75 percent of daily stock trades.

How does it work? Financial firms program computers to trade millions of shares every second based on certain triggers, such as when a stock drops or rises a certain percent. Like so much of what happens on Wall Street, this financial activity has little to do with what’s actually happening in the economy. It’s about following market trends, whether they are rational, irrational, or the result of human error.

One way to encourage investors to go back to thinking with their heads would be to place a small tax on each trade of stock, derivatives, currency and other financial assets. A fee of a quarter of 1 percent or less would be virtually unnoticeable to ordinary investors. But for the big-time stock-flippers and derivatives dealers, it would add up.

Imagine, for example, if such a “financial speculation tax” had been in place before the flash crash. In just the 20 minutes of the wildest trading that day, it would have generated $142 million in revenue. That works out to more than $7 million a minute.

Ideally, though, a speculation tax would change behavior. It would make high flyers in the financial casino hesitate before making short-term, high-risk gambles that put our entire economy at risk.

Since the tax would apply to each transaction, it would make purely speculative investment less profitable and encourage long-term, patient investment.

Of course, a financial speculation tax alone wouldn’t stop those who’ve gone nutty with greed. Take AIG, for example. It’s unlikely that a tax, no matter how high, would’ve prevented the daredevil gambling that nearly drove our national economy off a cliff.

But at least Uncle Sam would have wound up with a sizable chunk to invest in urgent needs. A 0.25 percent tax on AIG’s $440 billion in high-risk credit default swaps would’ve added up to $1.1 billion. That’s enough to pay more than 20,000 elementary school teachers for one year.

Support for financial speculation taxes is building in the United States and around the world. Proposals in the House and Senate would dedicate the revenues from such taxes for jobs programs. Both bills include protections for middle-class investors, such as exemptions for retirement funds and the first $100,000 in individual trades per year.

Several European governments, including Germany and France, support such taxes but would like the United States to take similar action. They have been pressing President Barack Obama to get on board at summits of the G-20, including one in Toronto this month.

The Wall Street casino got us into this crisis. A tax on the most reckless behavior should be part of the solution.

Sarah Anderson is the director of the Global Economy Project at the Institute for Policy Studies and the lead author of the new report "Taxing the Wall Street Casino."

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