Energy-exporting countries which have stashed billions in windfalls in sovereign investment funds may be forced to draw down on them as oil revenues shrink, sending a chill through stock, bond and property markets worldwide.

Oil-based sovereign wealth funds are a major force in international finance, holding more than $5 trillion in assets, according to David Spegel, an emerging markets expert at BNP Paribas.

The funds’ money is typically split into baskets serving distinct functions, propping up government spending at times of falling export revenues or managing windfalls over decades for future generations. Norway’s government is allowed each year to take up to 4 per cent of its $850 billion wealth fund, the world’s largest, though it only spent 2.8 per cent in 2014, using the money to pay for tax cuts. Nigeria’s stabilisation fund accounts for around 20 per cent of its total sovereign wealth pot. With Brent crude oil prices languishing at around $70, it is currently well below the fiscal break-even point needed by many major energy exporters, including Saudi Arabia, Russia and Nigeria, to balance their budgets.

Many funds are already making use of the stabilisation components. In October, Norway’s government said it may lift the cap on how much of its sovereign wealth fund it can tap to counter the economic impact of a weak oil price. Oil has dropped more than $20 per barrel since.