Caesar had his Ides of March to worry about. For the modern investor, the time to be fearful is August.

It could be a mere coincidence that the stock market had such a bad time last week, with the Nasdaq composite index sinking 6 per cent and the Dow Jones industrials losing 2.7 per cent. The Dow has a strong influence on all other stock markets and the Dublin market proved no exception last week.

For the Dow, the coincidence was that the market had closed at record highs the preceding Friday - precisely one year after the summer 1998 market peak, when the Dow topped out at 9,337.97.

What followed the 1998 peak was the worst market decline since 1990, as stocks plummeted in the wake of Russia's surprise currency devaluation and rising global deflation fears. The Dow sank 1,799 points, or 19.3 per cent, between July 17th and August 31st of last year. August 1997 was no picnic for investors, either. The Dow tumbled 7.3 per cent that month as worries about East Asia's then-nascent economic crisis hit Wall Street.

August 1992 brought us the start of a European currency crisis - and a 4 per cent Dow drop. August 1991 saw the coup attempt against Mikhail Gorbachev in the old Soviet Union.

In August 1990, the Dow plunged 10 per cent after Iraq invaded Kuwait. And August 1987 marked the final peak of the 1980s bull market and the beginning of a bear market that culminated in the horrendous October 1987 crash.

All coincidences? Perhaps. But that is six out of 12 Augusts since 1987 that many investors would have preferred to have been out of the market.

September and October often have not been kind to stocks, either. Indeed, August through October has generally been the US market's weakest stretch each year, at least since 1950. By contrast, stocks' best season historically has been November through January.

Is there good reason to suspect that the next three months could be difficult or worse for stocks? Long-term investors may rightly ask, "Who cares?" After all, the smart move all through the 1990s has been to buy into steep market declines, not sell into them.

But if that is your strategy, you ought to ask yourself this question: Do you have some cash ready to put to work if the market adds to its string of late summer/early autumn conniptions?

For many investors who have ridden the 1990s bull market, the constant worry is that their paper capital gains might evaporate and never return - or take years to do so. In other words, the fear is that we are near a long-term market peak, as in 1987.

Al Goldman, veteran market analyst at brokerage A.G. Edwards in St Louis, concedes that the market has an "altitude problem", but he sees that more in the context of how sharply key indexes have run up since early June.

Mr Bernie Schaeffer, head of Schaeffer's Investment Research in Cincinnati and someone who has made some excellent market calls in recent years, also thinks worries about the next few months are overstated.

He concedes there is always room for a surprise: another surge in oil prices, a currency devaluation by China, a plunge in the suddenly weak dollar. Still, "from a reward-to-risk standpoint, I see more upside potential than downside," he said.

Despite the latest uptick in long-term interest rates - the bellwether 30-year Treasury bond yield ended at a 21/2-week high of 6.01 per cent last Friday - Schaeffer sees yields staying in this range for a while.

But didn't Federal Reserve chairman Alan Greenspan, in testimony to Congress last week, leave the door open for another boost in short-term rates when the central bank meets August 24th?

As usual, Mr Greenspan merely spelled out the Fed's concerns about the economy and potential inflationary pressures.

Yet whatever the Fed does, the Treasury bond market may have a key ally in keeping yields down between now and the end of the year: the year 2000 computer bug.