Weighed down earlier in the year by Europe's debt crisis, oil now faces economic uncertainty from the so-called U.S. "fiscal cliff" -- a convergence of urgent tax and spending issues in 2013 that, if mishandled by opposing lawmakers in Congress, could plunge the economy into another recession.

On the positive side, crude prices have been supported by Iran's controversial nuclear program and unyielding violence in Syria, which has started to affect some of its neighbors in the oil-producing Middle East.

These have led to whipsaw volatility in London's Brent and U.S. crude futures, with fund managers often at a loss on whether to short the market on economic concerns or go long on worries about supply disruption.

Brent, the more important benchmark of the two, is trading almost flat for the year at just above $108 a barrel. U.S. crude, meanwhile, is down nearly 14 percent, hovering at $85.

Hall, one of the market's most famous bulls, says he's confident prices will rise over the long run on seasonal supply-demand. But he's not sure about the near term, particularly the next six weeks.

"IMPOSSIBLE TO FORECAST"

"Geopolitical risks remain high, although it is impossible to forecast how events will unfold," the billionaire oil trader told Astenbeck's investors in his monthly letter for November, a copy of which was obtained by Reuters.

Astenbeck and Clive had taken opposite sides of the market earlier this year, resulting in contrasting fortunes for their investors. But their performances have converged of late.

Losses at the two funds are also small enough to allow them to rebound if their managers read the market correctly.

The largely oil-focused Astenbeck -- based in Westport, Connecticut, and managing $4.6 billion -- is down 2 percent for the year through October, according to confidential performance and other data on the company obtained by Reuters.

Last year, the fund finished down nearly 4 percent -- handing Hall his first ever annual loss as a trader.

This year, Astenbeck emerged from a bruising second quarter -- it lost 14 percent in May in its worst month ever as Europe's crisis worsened -- to post three months of profit through September. But it stumbled again last month as crude prices slipped on fears about global growth.

In Clive's case, the London-based hedge fund with $3.3 billion under management is down about 3 percent for the year, said investors in the fund, who asked not to be identified. Last year, it lost almost 10 percent.

Other energy hedge funds haven't been doing too well either.

As of Tuesday, HFN Indices, a database run by New York's eVestment Alliance, reported that 11 of the 36 funds on its energy sector index were up by just 1 percent on the average through October.

NOT SHY TO SHORT

Levett, previously a star commodities trader at Louis Bacon's Moore Capital, founded Clive in 2007, running it with partner Richard Boland.

Unlike Hall, who's almost perpetually bullish about oil, the 42-year-old Levett is not shy about shorting the market when he thinks there is little upside to the price, say investors familiar with his trading style.

As a fund, they said, Clive also appeared less energy-centric than Astenbeck -- investing in natural gas and metals such as copper, tin and lead -- although some of its biggest positions have been in oil.

Exact bets taken by the two funds, as well as how much exposure they had particularly to oil, was not known. Hedge funds typically do not speak about their performance or operations to the media, and both Astenbeck and Clive did not comment for this story.

Investors said Clive gained about 7 percent, some $230 million, in May -- versus Astenbeck's 14 percent loss -- after betting correctly on the tumble in oil prices that month. But in July, it fell 3 percent, or nearly $100 million, as the market went against Levett's short positions.

Data this week from the IntercontinentalExchange, which trades in Brent crude oil, showed speculators, including hedge funds, trimming their net long positions for a third straight week. But figures from the U.S. Commodity Futures Trading Commission showed a rise in net longs of both combined futures and options of Brent and U.S. crude.

BET THE RANCH?

Astenbeck, named after a century-old castle in Germany owned by Hall, was launched in 2008 after Hall's decade-long storied career as a Citigroup (C.N) oil trader who earned controversial bonuses worth hundreds of millions of dollars.

Aside from the hedge fund, the 61-year-old Hall also runs Phibro Trading, a commodity trading firm largely owned by Occidental Petroleum Corp (OXY.N).

"If you're in oil, now isn't the time to bet the ranch. But Andy Hall might just be the guy to do that," said Charles Gradante, co-founder of New York's Hennessy Group, which invests in commodity hedge funds, although not with Astenbeck and Clive.

"I know some managers are paring their oil positions because they fear politicians will allow the market to be seized up by the fiscal cliff, before a solution comes. If you have billions in capital and you're down just 2 percent, you could load up in this less-crowded market. But you're also less nimble than the smaller guy and less likely to get out quickly in a crash."

(Reporting By Barani Krishnan; Editing by Bob Burgdorfer)

• A Permanent Economic Emergency