By Greg Peel

The Dow closed up 13 points, or 0.1%, while the S&P gained 0.1% to 1461 and the Nasdaq added 0.2%.

It began on Monday night, with a sudden US$5 plunge in the price of Brent crude seeing both Brent and West Texas ultimately settle around US$3 lower. It carried through on Tuesday night, as the oils fell another US$2 or so and then last night we saw Brent down US$3.84 to US$108.19/bbl and West Texas down US$3.54 to US$91.75/bbl.

There has been a lot of speculation about what actually happened on Monday night. Was it a computer glitch? Not according to the exchanges. Was it a "fat finger" error? Not according to further weakness on Tuesday. Was it expectation of a US government reserve release? We have no plans, said the government. Then last night the weekly US inventory data showed a much bigger than expected jump in stocks of crude.

The next step was for the US Energy Information Agency to deny that its data were leaked ahead of their release, but in the meantime it has been revealed that the Saudis are apparently selling. OPEC has been concerned with the rising price of oil, and no doubt became more concerned after last week's QE3 announcement, offering up the potential for a weaker US dollar and thus higher nominal oil prices. OPEC gets nervous over US$100/bbl (West Texas), as the organisation knows such prices encourage further shifting towards alternative energy sources.

So there we have it, supposedly. A lot of traders would have been caught long on Monday night as a person or persons unknown dumped a big sell order on the Brent market, given the QE3 impetus for higher prices and that fact oil has become a popular inflation-hedge trade in recent years, perhaps even usurping that role from gold. It took another session for traders to make sure it wasn't just a mistake, and by last night the herd was stampeding.

Lower oil prices are good for the overall global economy, but not so great in the short term for energy sector companies. This balance goes some way to explaining why Wall Street has not gone anywhere much these past couple of sessions.