They successfully predicted the magnitude of the Tokyo stock fall in the late 1980s. They bet correctly that sterling would fall out of the Exchange Rate Mechanism in 1992. George Soros, one of the most famous and infamous hedge fund managers, attained an almost mythical status as well as a swollen bank account.
But in a few weeks all that has changed. The Russian default and subsequent market turmoil wrong-footed many of the best-known hedge funds. The regulators are on their backs and credit lines are being withdrawn. Suddenly, the world's biggest and bravest gamblers are in retreat.
Even before the latest bout of market turmoil, things were not looking too rosy. Although the term "hedge fund" is often applied to a wide range of investment partnerships, a particular class of funds - the so-called "tactical trading" funds or speculators - was widely blamed for exacerbating the emerging markets crisis.
These funds drove down exchange rates - and in some case stock markets - to excessively low levels, making life more difficult for struggling emerging market economies.
Malaysia imposed capital controls to protect its embattled markets from the speculators. The Hong Kong administration intervened directly in the financial markets to make sure that the speculators lost out from what they termed "market manipulation".
Some of the most influential figures on the world stage had begun to argue that "something must be done" about the speculators, and the issue was expected to figure heavily in the forthcoming annual meetings of the International Monetary Fund and the World Bank, even before the latest developments at Long-Term Capital Management.
However, the chronic financial difficulties of Long-Term Capital Management, and others, have focused regulators' minds on the dangers the funds can pose to the health of the international financial system.
The majority of large asset managers and investment banks have some exposure to one type of hedge fund or another. Some institutions invested in hedge funds because they wanted to diversify their portfolio. For instance, a bank trading mostly in equities could help to spread its risk by investing in a specialist hedge fund operating in the US mortgage market. But others invested in hedge funds simply because they wanted to raise returns on their investments.
According to Christopher Cruden, managing director of Tamiso & Co, a US hedge fund: "People were seeking higher and higher returns. In many cases, it was just naked greed." The upshot of all this is that if a major hedge fund goes under, it could pull other institutions with it.
Hence the eagerness of the US Federal Reserve to organise a bail-out for Long-Term Capital Management. And hence the announcement today from the Financial Services Authority (FSA) in London that it was seeking to clarify the exposure of 55 financial institutions to hedge funds.
In the wake of recent events this could be just the beginning for hedge funds, which will face unprecedented regulatory scrutiny in coming months.
But many of the hedge funds have more pressing problems than regulatory meddling. In numerous cases, their creditors are banging on the door. And even those funds which have escaped relatively unscathed so far will find that their ability to obtain new credit has been severely dented. Mark Turner, managing director of Schooner Asset Management, said: "We are in the middle of a major global margin call [a calling-in of loans]. A massive credit crunch is on its way."
Another leading fund manager said: "Put it this way: the heads of credit at many of the banks are being hauled over the coals right now. I can't see them being willing to go out and lend more to the industry."
The problem of liquidity is not confined to the hedge funds. According to Rick Deutsch of Merrill Lynch, hedge funds are "big drivers of business in many markets". If hedge funds are forced to scale back their activities, there will be all sorts of knock-on effects. Companies - or countries - trying to raise capital may find themselves unable to do so because the traditional high-volume buyers of debt and equity are simply not around any more.
But, although the hedge funds may be down, they are certainly not out. The political and the regulatory will to crack down on the funds may have hardened, but it is not immediately obvious that officials have the power substantially to affect the hedge fund industry.
Regulators may be able to force institutions to detail their exposure to the funds. They may be able to force a small number of funds to detail their own exposures to markets. But, as one leading fund manager put it: "A lot of these people are simply untouchable. A lot are based offshore and, in short, there's not a great deal the Bank of England or anyone else can do to control them."
Other experts argue that a regulatory backlash against the entire hedge fund industry is not desirable. Some funds are not highly leveraged, do not place one-way bets on currencies or markets, and do provide a vehicle through which institutions can diversify risk. "At one time, using hedge funds was simply a more efficient way of doing business," said Mr Cruden.
Neither is it obvious that liquidity problems will persist over the longer term. Although most experts agree that hedge funds will have difficulty obtaining credit for the next six months, or perhaps even for the next few years, financial markets tend to have short memories. One credit analyst said: "It might take a year or two, but liquidity will slowly creep back up again."
As Mr Cruden said: "I don't think all this spells the end of hedge funds at all. As long as people, banks and institutions continue to seek out higher returns, the industry is not only going to continue to exist - it will grow."