Image caption The fund cut its exposure to recession-hit Europe in shares and debt

Norway's oil fund, one of the biggest investors in the world, rose in value by 13.4% last year, its second-best performance ever.

The central bank said the fund's investments in shares jumped by 18.1% in 2012, boosted by soaring equity indexes around the world.

It is now worth 3.8tn krone (£450bn; $670bn), up from 3.3tn krone in 2011.

Norway's fund invests the money from its huge oil industry in the nation's future.

The sovereign wealth fund is now 40% bigger than the value of the entire Norwegian economy. If it was invested inside the nation, this would cause distortions like massive inflation.

The fund lost 2.6% overall in 2011.

But in 2012, surging stocks pushed the value of the fund. Last week, the US Dow Jones average closed at a record high, furthering gains last year despite the sluggish US economy.

"The fund's performance reflects development in global financial markets during 2012," the fund's chief executive Yngve Slyngstad said.

Managed by the country's central bank, the fund cut its exposure to recession-wracked Europe to 48% of its total portfolio last year, from 53% the year before.

Its bond, or fixed-income, investments returned 6.7% to the fund.

"While in 2011, the fund invested 150bn krone of the year's capital transfers in European equities, in 2012, the fund invested nearly an equivalent amount in emerging bond markets", said Mr Slyngstad.

The fund reduced its holding of UK government debt by 13% in the last three months of 2012, and French government debt by a quarter, but more than quadrupled its holding of Australian government debt.

It also reduced its holdings in Apple by 20%, profiting from a rise that saw the US tech giant become the world's most valuable firm, and also sharply cut its stakes in Vodafone, BG Group and ExxonMobil.