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Program Trading - Should You Care?

Probably you know by now that the big boys don't play nice. In the stock market, institutional and other investors with large sums have much more influence on events than the average trader. One way they do that is through the use of something called 'program trading', the purchase (or sale) of a group of stocks, usually by automated buy/sell orders.

Originally the term had little to do with 'computer program'. Program Trading got its name when index funds and other institutional investors embarked on large-scale trading to replicate a stock index. Before long, clever statistical analysts joined hands with even more clever arbitrageurs to try to 'beat' the market through the use of sophisticated trading algorithms, assisted by (then) new, high-speed computer programs.

Fundamental analysis met technical analysis and introduced themselves to software. The rest is rather bumpy history. In one famous case, though some studies deny this, it may have contributed heavily to the well-known Black Monday of October 1987 when the market dropped by over 20% in one day.

While not the largest drop in history (a larger percent decline occurred in 1914 and later a larger point drop, in 2001), nevertheless within one day, 500 billion dollars evaporated from the Dow Jones index. And, the event continued in markets around the world. Hong Kong shares fell over 45% (some say this happened before the U.S. decline - accounts differ) and London over 26%.

Out of favor for, oh say maybe a day, program trading continued - albeit after a few software tweaks. New SEC rules were devised and major market players altered thresholds to slow or halt trading when certain percentage declines are reached.

While the NYSE defines a program trade as a basket of 15 stocks or having a total value of $1M (or more), trades can be executed in small lots (100-300 shares, for example). In theory, this allows orders to be completed before other investors get wise, and helps avoid large price movements before positions are solidified or liquidated.

As finance professors and large-firm specialists develop ever more sophisticated methods of taking advantage of small price discrepancies across global markets, program trading becomes ever more complex. In many cases, the individuals involved don't themselves understand well the consequences of implementing a particular strategy.

Program trading now comprises over 50% of NYSE volume on average and it can introduce large swings in a few stocks or large portions of the market. Clearly, the big boys wouldn't bother unless they believed - backed now by decades of studies - that there was an advantage in using the technique.

But whether villain or savior, it's here to stay. Over 50% of the volume on one exchange that trades over 1.6 billion shares a day is a huge amount of arbitrage activity. That effect can work against the average investor or for him, but only if included in a trading strategy that pays attention to where those trades are going.