Wall Street plunged overnight, with the S&P 500 falling more than 3% at one stage, with London's FTSE 100 entering a bear market after falling 3.5%.
Not surprisingly, mining and energy companies were responsible for most of the damage, as US crude oil prices fell to US$26.30 a barrel – the lowest figure since May 2003. Brent oil fell 1.2% to US$28.41 a barrel. The International Energy Agency warned that the oil market could drown in oversupply.
In London overnight, BHP Billiton's share price plunged 7.7%, suggesting it's going to be a horrible start for the BHP Billiton Limited (ASX: BHP) share price on the ASX this morning. Rio Tinto Limited (ASX: RIO) could also come in for some harsh treatment after its London share price fell 4.1%.
The MSCI World equity index dropped 3.4% to its lowest level since June 2013, and is now down 20.5% since May 2015 – hence entering bear market territory.
The S&P 500 managed to recover some of the falls – down 1.2% before the close while the Dow Jones gave up 1.6%.
Apart from plunging oil prices, investors are fearful China's economy could face a hard landing – in other words, instead of growing at around 7% as it reportedly is now, growing at low single digits.
And it seems to be spreading – just 13 shares from the S&P/ ASX 200 (index: ^AXJO) (ASX: XJO) are in positive territory, 2 are flat and the rest are down since the start of this year.
Foolish takeaway
The upside is lower oil prices translates into falling petrol prices, which means more money in people's pockets and should prove a boost to those companies that aren't in the mining or energy sectors. Falling share prices are also great news for investors, with a host of high-quality companies available at much cheaper prices.