Waiting for the bull run to end.
Most pundits agree it is a question of when, rather than if, markets fall to lower levels. Just how much lower is, of course, the $64,000 dollar question.
Some analysts are predicting a rout on Wall Street in the spring or early summer. Others predict a gradual correction over a number of months.
While few observers are using the inflammatory phrase, "a stock market crash," those words sum up the fears lurking just beneath the surface.
The focus is firmly on New York, where the market has been viewed as overvalued for some time.
High-tech stocks, driven by developments on the Internet, have been behind the dazzling performance of the American market in recent years.
But US corporate earnings are bound to be hit by the turbulence in the Far East. American economic growth is expected to be shaved back by at least half a per cent due to the troubles in Indonesia, South Korea, Malaysia, Japan and Hong Kong.
One positive effect of the crisis, however, is that US interest rate rises may not be required to cool the economy.
In London, the effect on the market of a meltdown on Wall Street is bound to be severe, even though prices are viewed as far less frothy here than in New York.
A slamming on of the brakes would jolt confidence in Britain at a time when the talk is of an economic slowdown in 1998 and 1999.
Even with Wall Street still buzzing, despite yesterdays falls as the Asia crisis deepened, British and US companies are warning profits will be hit by the troubles.
Some of the economic slack may be taken up by continental Europe where the cycle is due to turn for the better in 1998 and beyond.
Nevertheless, many analysts are trying to second-guess the extent of the debris in the event of a crash on Wall Street. They are making comparisons with 1987 rather than 1974 or 1929 and predict the ensuing pain is likely to be somewhat less than ten years ago.
Significantly, they argue, a crash would not come as a great surprise, so the shock element of 1987 would be missing, and, presumably, some of the panic.
Moreover, many fund managers have been heavy share sellers in the last 18 months precisely because they have feared a dramatic end to the bull run.
Because institutions are flush with cash, a much swifter recovery is on the cards than in 1987 as investors hunt for bargains, and, consequently, push up share prices.
On the other hand, prices will not recover quickly if the economic fundamentals are bleak.
The worst case scenario is that Asias woes could trigger a worldwide recession.
That is why American-backed international bodies such as the International Monetary Fund and the World Bank are stepping up moves to contain the crisis.
But success will depend on the willingness of Asia to reciprocate by tightening up the management of their economies in the future.