Asian shares plummeted to four-year lows on Wednesday as a renewed tumble in oil prices spooked investors and hit energy shares hard. Japan's Nikkei index plunged 3.80% to 16,405. Australia's S&P/ASX 200 index gave up 1.26%, while South Korea's KOSPI slid 2.30%. Hong Kong's Hang Seng index dived 3.41%, while China's Shanghai index had a slightly better showing due to announced fiscal and monetary stimulus measures, which helped cushion the slide to less than 1%.

Oil prices resumed their downward spiral after the International Energy Agency warned that markets will be "drowned in oversupply" in 2016, due to Iran's reentry into the global arena after the sanctions relief. The warning sent U.S. crude oil to a fresh 12-year low at $27.55 a barrel, before trading lastly at $27.68, down 2.7% for the day, and following a fall of 3.26% yesterday.

Brent crude futures dipped 2% to $28.13, not far from another 12-year low, before settling at $28.27, down fifty cents for the day, and following a gain of 0.7% yesterday.

Wall Street relinquished its gains late into the Tuesday session due to the slumping energy sector, with NASDAQ slipping 11 points, or 0.26% to 4,476. S&P 500 was up just a sole point at 1,881, while Dow Jones closed up 27 points, or 0.17% at 16,016.

Yen rallied as investors seek its safety amid the global gloom, with the Japanese currency jumping 0.76% versus the dollar to 116.71. Yen gained 0.32% against the euro to trade at 127.88, while hitting a two-year high against the battered sterling at 165.16, up a handsome 0.85%.

Sterling took a hit after Bank of England Governor Mark Carney said he has no timetable to raise interest rates rates, hinting at a lack of hurry to prop up the pound, which led it to its lowest level since March 2009 versus the dollar at 1.4141; while last trading today at 1.4156. Sterling fell 0.45% against the euro to a year low at 0.7743.

Slated for release today, America's monthly CPI for December, forecast to stay flat, same as November's, while Canada's crucial manufacturing sales are expected to have risen 0.5% m/m in November, much better than October's 1.1% drop, and which would lend some support to the hammered loonie.