IT'S not over till the fat lady sings'' is a favourite saying for retreating Americans, but there is mounting evidence that investors from the United States are beginning to leave the Asian markets.

They are not alone but, as the most recent and significant players in Southeast Asia's bull run, their signal is that other pastures look greener after the appreciation in share values last year.

How a market takes on a stance when previously its collective members were full of confidence is fundamental to all those with exposure to share values.

Emerging markets throw up more conflicting signals than any other. Clearing a passage through the morass are strategists of the big brokerages and fund management companies.

It is impossible to pinpoint why a bull market stalls at a particular moment but when international capital inflows have been a significant factor, the decisions of the big name strategists advising these funds becomes central to the answer.

It is these strategists who are charged with the task of informing the investing public when it is time to get out and take profits.

They also change country weightings, and judge when a market is fully valued. Their assessments are rarely followed verbatim but make a vital ingredient in forming a view of a market.

The strategists are not quite economists but neither are they analysts. They tour economic tables and company balance sheets to provide an insight into a market's valuation in relation to other destinations.

Advice is always easier to accept when it confirms an opinion, and the type of strategy advice adhered to by the big funds usually reflects the fund managers' own world view.

According to Nick Knight, Nomura's chief global strategist, the globalisation of finance is leading to a convergence in the way fund managers approach asset allocation.

However, US investors to a greater degree still liked to see entry/exit decisions on markets supported by quantitative assessments, whereas the British funds were inherently suspicious of such ''black box'' approaches, he said.

The Japanese, on the other hand, preferred a ''strong image to be presented of a market's growth potential''.

Not much has been systematic about the foreign invasion of Asia's equity markets in the latest bull run, and little is clear cut in the unwinding of those positions.

The science is inexact and ill-defined; the strategist draws a big picture of the ebb and flow of values. It was the prod from trusted figures, such as Morgan Stanley's Barton Biggs, that was the catalyst for many US funds entering Asia.

Certainly, the combination of low yields in the industrialised markets and increasing liabilities being felt by pension funds and insurance companies underlay the search for higher returns.

But many of the participants in the region over the past year have been retail investors via mutual funds.

For many of these investors the confidence to take that step into the unknown was prompted by bullish buy signals from big-name strategists.

Now the question being asked of those same pathfinders is, has the bull run reached an end and is it time to take profits? In Hong Kong's case, the dilemma for the strategist was whether the leap in share values was a ''structural re-rating'' or a ''temporary revaluation'', said Robin How, who is the investment director at NatWest Investment Management Asia.

The right way to answer that question, from a methodology angle, should be to assess the data available quantitatively, he said.

This involved comparing previous stock market cycles, measuring turning points and establishing past resistance levels.

However, there was not enough cogent data on the Asian markets to support assessments of how they would behave in the future, he said.

That represents the core of the strategists' problem in emerging markets such as Southeast Asia. Tracking benchmark indices is easy if information is perfect and the market is open, but when there is a lack of comparative data a more creative approach isrequired.

Unlike the developed markets, in Asian markets the historical data and current market statistics needed for little black box calculations are lacking.

The strategists' judgments become subjective - in the industry parlance, they enter the realm of ''active judgments''.

Barings regional strategist Alan Butler Henderson often runs against the grain of consensus.

He sees each stock market cycle as comprising two phases that he described as beginning in the financial economy - in Hong Kong the liquidity that has been pouring in from overseas - followed by factors in the real economy that determine prices in the latter stage of the cycle.

For Mr Henderson, strategy was founded in academia, but sticking too close to pure theory had led to a ''dour and unimaginative form of analysis''.

He said it was necessary to have a ''clear view on the dynamics of markets and economies'', and pointed to his recent success in calling the Japanese market an opportunity to buy.

The degree to which fund managers follow the strategists' reports is difficult to gauge.

Jim Walker of Credit Lyonnais said: ''Few would like to admit to have followed Barton Biggs into Hong Kong but a lot obviously did.'' According to Fidelity's K. C. Lee, the giant US fund manager certainly does not admit to it: ''You have a view on which markets are attractive but we don't target weightings.'' Instead of a rigid asset allocation by country, the company prefers a ''stock picking strategy'', which is attractive, rather than strictly adhering to country weightings.

In assessing the way strategy advice affected capital flows into Hong Kong and the region's markets during 1993, Mr Knight said the main impetus was ''thematic investment'' based on a broad view of the region's ''growth story'', rather than any fundamental analysis of the its markets.

He was sceptical about treating strategists' exact weightings too seriously.

The obsession with weightings changes was a recent phenomenon dictated by the sensitivity of markets to international capital flows and the competition to generate returns as high as the competition.

''Weightings only represent a fraction of the information available to investors. The real significance of the analysis lies in the quality of the thought processes and logic behind them,'' he said.