5 things you need to know about the Australian sharemarket today

Welcome to Tuesday. Here are the five things I'm looking at today on the Australian sharemarket.

1. The S&P/ ASX 200 (Index: ^AXJO) (ASX: XJO) has opened lower again, as the global selloff continues. At the open, the index was down 0.5%Overnight, the Dow Jones and the broader S&P 500 both lost 0.6%, while the tech-heavy NASDAQ was hammered down 1%.
2. Oil prices continue to fall, with West Texas Intermediate (WTI) Crude falling to US$55.41 per barrel, and Brent oil dropping 2% to US$60.5 per barrel.And analysts say they can't see a bottom yet, with more predictions of US$50 per barrel coming out every day. That would mean the price of oil has almost halved in just 6 months as the chart below shows, and is now trading at its lowest price since 2009.Australian oil producers are under more pressure today, including the likes of Santos Ltd (ASX: STO), Woodside Petroleum Limited (ASX: WPL), BHP Billiton Limited (ASX: BHP) and Origin Energy Limited (ASX: ORG).
   
   Source: NASDAQ

   Karoon Gas Australia Limited (ASX: KAR), which has yet to produce even $1 in oil revenue, despite being listed on the ASX for more than 10 years, could also take a hit. The explorer is drilling for oil offshore Brazil and in the Browse Basin, where wells aren't exactly cheap. Unless the company can sell off more of its assets, or raise more debt, shareholders may well be putting their hands in their pockets again – and making the existing share buyback a waste of cash.

3. National Australia Bank Ltd (ASX: NAB) is moving closer to exiting its troubled UK business. The bank has reportedly sold off around $2.3 billion in higher risk loans from its UK Commercial Real Estate portfolio.NAB owns two banks in the UK, Clydesdale and Yorkshire Banks, which may be spun off to UK investors as an IPO next year.
4. Tweet of the Day
   

   There have been over 350,000 tweets using #illridewithyou as Australians unite https://t.co/IjdlhTk3SU pic.twitter.com/y4YwK4l4o7

   BBC Trending (@BBCtrending) December 15, 2014

   Nothing more needs to be said really.

5. Stock of the Day – brought to you by Owen Raskiewicz – is actually two banks – National Australia Bank Ltd (ASX: NAB) and Australia and New Zealand Banking Group (ASX: ANZ). In this article, Owen tries to pick one of the two.