Europe's currency chaos reflects the revolutionary impact that technology has had on financial trading.

Central banks used to control exchange rates, either by influencing interest rates or by direct intervention. Sometimes even the threat of intervention was sufficient, especially when supported by other central banks.

No more.

First, there is the sheer size of the market. Technology has created a global market so large that it is impossible for a central bank to artificially maintain an exchange rate. A large intervention, say $5 billion, pales in comparison to the more than $700 billion traded every day in the currency markets.

In fact, the reserves of most central banks together are insufficient for prolonged intervention in the currency markets, even jointly.

The integration and unification of the currency markets is a direct result of technological advances that allow participants anywhere not only to have access to market information but also to easily move large amounts of money across national boundaries.

This results partly from recent improvements and automation in settlement and clearing.

Instant Analysis

Second, telecommunications technology has made information readily available. Almost any significant event around the world is now reflected instantly in the markets.

All this is helped by a quantum leap in analytical technology. This consists of using sophisticated math to analyze and respond to information.

The central role of analytical technology in today's markets has been recognized by financial and academic institutions, many of which devote considerable resources toward the development of this technology.

An example is the financial analysis and security trading program (Fast) at Carnegie Mellon University, set up with banking and computer-industry partners.

It is now possible to react instantly to information or events and to find and take advantage of opportunities wherever they occur. This ability is not limited by regulatory boundaries. In fact, one of the largest and most liquid markets in the world, the Eurodollar market, does not fall under any easily defined regulatory structure.

Big Demand for Derivatives

Third, the growth in size and the ease of transacting have been accompanied by an explosion of the market for derivative securities. Analytical technology has made it possible for banks and other intermediaries to create customized financial products to meet clients' specific needs.

One important part of this development is that organized exchanges, which are more subject to regulation and control, play a smaller role than in the past. Intermediaries can trade with other intermediaries, offset the needs of one client with a counter party, or unbundle a security and trade different pieces in different markets.

Because these securities can be used to supplant some traditional banking functions, the distinction between banking and trading is increasingly obscured, and it becomes even more difficult to regulate and control monetary activity.

Governments Outgunned

The failure of even astronomical interest rates to support exchange rates demonstrates that monetary policy and, in the longer term, fiscal policy, are now subject to the discipline of international market forces.

Part of the argument for not participating in a currency arrangement such as the European Monetary System is that it requires ceding the ability to control one's currency. In the light of the recent turmoil, this point may well be moot.

Prof. Sullivan is dean of the graduate school of industrial administration at Carnegie Mellon University, Pittsburgh. Prof. Srivastava, professor of economics and finance, directs the school's financial analysis and security trading program.

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