When it comes to sovereign wealth funds — state-owned investment vehicles — those countries that can afford to squirrel away surplus revenues do.
As of September 2017, sovereign wealth funds around the world had amassed $7.4 trillion in assets under management, according to the Sovereign Wealth Fund Institute (SWFI), up from $3.4 trillion almost a decade ago. Funds invest in a range of financial assets, from stocks and bonds to real estate and precious metals, but all have an objective to maximize the long-term return from their investments.
Of total assets held by SWFs around the world, $4.2 trillion's worth were held by oil and gas-related funds. The most prominent examples of these belong to oil-rich countries like Norway, Kuwait and Saudi Arabia whose wealth has been amassed from energy exports. These types of funds are designed to act as a buffer to oil price volatility, as currently seen in markets. There are non-commodity based SWFs too, however, which currently hold a total $3.2 trillion of assets. China's SWF is a good example of a non-commodity based fund, with $813.8 billion worth of assets amassed since 2007.
CNBC looks at the world's largest sovereign wealth funds in the world, ranked by total assets under management as of September 2017 according to the SWFI.