Norway's massive oil fund surged in value to NOK 2.385bn or $396bn in the second quarter of this year - boosted by a surge in the value of global share prices - an increase of NOK 309bn since the end of the first quarter, in figures released on Friday by the central bank.

The country's Govern Pension Fund - which is known to its people as just "the oil fund" - ploughs all the profit Norway receives into international investements to guarantee the future wellbeing of its citizens. The sovereign fund is one of the biggest in the world and the largest owner of European stocks.

"International equity and fixed income markets showed a marked improvement in the second quarter. The return on the Government Pension Fund – Global was 12.7% (NOK 270 billion) and the excess return 2.1 percentage points, the best quarterly result ever," the Norwegian central bank announced.

The central bank said Q2's positive development continued into the third quarter.

"Since the markets turned in March and up until today, the value of the fund has increased by more than NOK 600bn," said CEO of Norges Bank Investment Management Yngve Slyngstad.

"Economic developments showed clear signs of stabilising in the second quarter and the uncertainty around the financial sector decreased. Liquidity is beginning to return to a number of fixed income markets," Slyngstad added.