NEW YORK (

TheStreet

) -- Unrest in the Middle East and its impact on oil prices could still be the biggest threat to the markets, even as a humanitarian and economic crisis looms in Japan and Europe's sovereign debt problems remain unresolved, according to

TheStreet's

readers.

In a

poll, readers of

TheStreet

were asked to rank which threat they considered most serious for the market.

The options included the crisis in Japan following its earthquake, tsunami and nuclear power plant troubles and its impact on the global economy, a possible oil shock as unrest continues in the Middle East, the end of loose monetary policy that has juiced up markets in the form of QE2, the debt crisis in Europe and a possible slowdown in China.

We also asked

TheStreet

readers to rank the biggest risk to the market in a

poll just one day before the Japan quake, with all the other options remaining the same.

Interestingly, in both the polls before and after the Japan quake, the prospect of an oil shock struck readers as the biggest threat to the market, with the option garnering more than a third of the votes in each case.

That is not unexpected considering that investors can easily perceive the impact rising oil prices have on an average American household's spending, while the impact of a slowdown in Japan or a default in Europe is uncertain.

In fact, readers still see a bigger threat from an end to QE2 than a slowdown in Japan or even China. At least 30% of the readers ranked QE2 as the biggest threat. Only 17% of the voters thought Japan's crisis was a credible threat to the markets. Less than 13% expected the European debt crisis to topple the market rally.

The threat of a slowdown in China, which has commodity investors on edge, was seen as a minor risk, getting only 12% of the votes. Investors appear to be more confident that China will be able to engineer a soft landing even as it battles inflation.

Still, the responses to the poll were fairly splintered, with no one threat swaying the vote. That probably reflects the extent of the uncertainty in the market, with multiple issues both at the domestic and global level weighing on the fundamental outlook.

Headlines out of the Middle East continue to be negative, while some sectors with exposure to Japan, including the semiconductor industry and some retailers, remain under pressure.

Meanwhile, speculation that the Fed will call an early end to QE2 resurfaced again on Monday, after St. Louis Federal Reserve President James Bullard suggested over the weekend that the central bank might still review the idea of cutting the program short in April, with the economic recovery on track.

For those who have worried that the Fed's bond buying program might be causing inflation, an early end to QE2 should come as a relief. It might also be a sign that the central bank is more bullish on the recovery. Still, investors fret that it could disrupt both bond and equity markets as investor risk appetite wanes and the strength of the recovery remains tenuous.

Market experts expect stocks to be volatile in the coming weeks in the absence of corporate news. Once earnings season begins in the middle of April, macro concerns might fade as investors once again focus on valuations and corporate profitability.

--Written by Shanthi Bharatwaj in New York

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