The world has truly turned on its head. While America and Europe struggle to pay their bills, a handful of resource-rich African countries are able to save. Fifteen years ago the notion that any more than the odd African government would have a sovereign wealth fund (SWF) was inconceivable. Such funds, which had the firepower to bail out Wall Street, are hardly synonymous with Africa, a continent better known for aid and poverty than any financial largesse.

Yet in a stark reflection of how wealth has migrated from developed economies south as well as east, oil producers Nigeria and Ghana are laying the foundations for sovereign funds; indeed, Nigeria is in the process of hiring a team of executives with the help of consultancy KPMG.

These are just two in a raft of African governments with a newfound ability to save, buoyed by a combination of debt relief five years ago and the prolonged commodity boom. As in Latin America, where sovereign funds have sprouted over the past year in unlikely quarters such as Peru, Bolivia and Colombia, in Africa there are now about 15 sovereign funds, with five more in the offing. Advisors from Norway, the UAE and Singapore criss-cross the continent offering expertise.

Some countries have been nurturing national nest eggs for a while. Algeria's oil-fed fund is worth around $56bn (€42bn), Libya's has $60bn which will now go to fund reconstruction after the end of Gaddafi's 42-year rule, and Botswana's Pula Fund (saved from diamond revenues) is worth $7bn. Oil producer Angola - which now tellingly owns the equivalent of around 4% of the listed companies of Portugal, its former colonial master, including banks, telecoms and energy companies - is planning a fund. Uganda, where the oil won't flow for several years yet, and even tiny, landlocked Rwanda, without a drop of oil but hoping to earn foreign currency from exporting methane gas from Lake Kivu, plan to get in on the act. Other governments, from Gabon to Equatorial Guinea, Morocco and South Africa, have stockpiled huge reserves and could follow the trend.

All want to invest the billions of dollars their central banks have stashed away for the long term, seeking to better manage their national wealth, counter commodity cycles and guard against inflation.

Optimistic forecasts estimate Nigeria's wealth fund could top $250bn one day. That's small beer compared with the $627bn Abu Dhabi Investment Authority, Norway's Government Pension Fund (accrued from North Sea riches and which holds about 2% of all European equities) or China's $408bn Investment Corporation, which manages the massive foreign-exchange reserves garnered from export-led growth. But in today's straitened times the prospect of new African funds swelling the number of these sought-after, long-term investors, that are free of the liabilities that limit pension funds and other institutions, is a thrilling prospect.

"African governments have rapidly accumulated reserves and are attempting to manage them for the long term for future generations. A shift in money and investment is clearly happening," says Patrick Thomson, global head of JP Morgan's $65bn sovereign business. He predicts that combined sovereign funds and central-bank reserves will hit $20trn by 2020 thanks to contributions from new and fast-growing funds just like Africa's.

Nigeria and Ghana's new funds won't have much initially. Nigeria needs to invest in infrastructure and here the plan is that money is funnelled through an Infrastructure Fund within the broader sovereign wealth fund. "They won't put more than $10bn-$15bn dollars away over the next five years because of the infrastructure deficit," predicts Lagos-based expert Bismarck Rewane. Nor will Ghana squirrel away much at first. Although new oilfields are due onstream, the sector is still small. Savings won't be significant until production hits 250,000 barrels per day, not forecast until 2013. And Ghana is planning to save only a small proportion of its oil earnings anyway. A law passed last March allows the government to use 70% of oil revenues to fund its budget, only saving 30% in heritage and stabilisation funds.

Conventional thinking would have Africa's savings invested in liquid, safe fixed-income and equity markets in developed countries. But in these changed times, new wealth funds say they are observing where the big guns' funds are investing, which means they may not be piling into Western economies just yet.

As the European and US debt crisis drags on and growth in developed markets grinds to a halt, sovereign funds are beginning to diversify.

The idea of government money being squandered on loss-making investments in US banks excited public opinion in China. Managers of Norway's wealth fund have said they plan to reduce exposure to European assets over time in favour of broader investment in emerging markets. Research from consultancy Monitor Group shows that the Asia-Pacific region attracted the largest chunk of sovereign wealth fund direct investments in 2010 at $25.2bn - nearly half of the total. "Returns on many traditional asset classes are currently depressed and seem likely to remain so, particularly developed-market equities and government bonds," says Monitor. "In this vein, SWFs have turned their eyes toward emerging markets." Nigeria's eagle-eyed central bank governor Lamido Sanusi recently decided to put 10% of the country's $33bn foreign-exchange reserves into renminbi, saying there was "less appetite" for holding dollars.

There will also be pressure to invest closer to home. "Buying shares in Marks & Spencer would prompt the difficult question back in Africa of why on earth aren't these guys buying a chunk of my company," says Ayo Salami at London-based asset manager Duet Group. Africa's funds will also be prevailed upon to buy local-government bonds to help finance domestic deficits; the hope is that new sovereign funds will encourage Africa's own asset-management industry too.

Opportunities to manage the money may also be used as a carrot to draw more of the big investment banks to Africa. In the long term, Africa's wealth funds could also want to pick assets that are more directly strategic and beneficial to Africa. Ways to invest externally for the continent without stoking inflation could include things such as satellites, which would transform the cost of telecommunications. In this way Africa's future sovereign funds could become major players in development finance, transforming into sovereign development funds involved in national strategies for growth. Investment abroad will also be limited by Africa's enduring need to stabilise. During the financial crisis even the strongest economies drew on their sovereign funds to shore up rocky times back home.

It's not just the idea of using capital in poor countries to subsidise capital in rich counties that goes down badly. In some quarters the very idea of saving per se, in a continent where poverty is widespread and infrastructure frequently dire, isn't that popular either. Sovereign wealth funds in poor but resource-rich countries may be lauded by the World Bank as buffer mechanisms against boom and bust, and by bankers who fly in seeking lucrative mandates, but the average African politician doesn't go a bundle on the idea. The argument goes that if you don't have enough schools or hospitals, why save billions in oil revenues in an offshore fund for the future? "The problem of addiction is to resolve the addiction rather than to lock the cocaine away. The preferable outcome is that they become an efficient member of society," says Rewane.

Recent revelations around the Libyan Investment Authority, which scored a two-out-of-10 rating on the SWF Institute's Linaburg-Maduell Transparency Index, can be used to argue the case for spending rather than saving, says Sebastian Spio-Garbrah, founder of DaMina Advisors, a New York-based political-risk consultancy. He argues that the fund's poor returns go to show that developing African countries would be wiser to spend their money at home. "Gaddafi would have been better off taking this money out and buying a car for every Libyan." And there is little thanks for investing abroad too, says Spio-Garbrah. "Libya's fund was invested across Europe but they ganged up to kill him." Libya's sovereign wealth fund was found languishing with almost half the portfolio in cash, as well as low-yielding European and African investments including Italian bank UniCredit, Juventus Football Club and LAP Green Network, a loss-making African telecoms company.

Nigeria's powerful state governors, who manage swollen oil-fed budgets (some the size of small countries), are also arguing that it can't afford to save just yet. Because of the lack of a clear legal basis on revenue distribution between federal, state and local governments, they have blocked the passage of the SWF bill, which still hasn't been passed into law. In the latest twist they've applied to the Supreme Court to block a $1bn transfer from the Excess Crude Account (ECA) into the sovereign fund, arguing that they can't afford to get less oil revenue when they are having to finance a new minimum wage and just before the government plans to remove subsidies on fuel. "It will pass. There will be a trade-off somewhere," says Rewane.

And despite enthusiasm for the wealth fund concept, saving will be tough for some governments. Uganda's central bank governor Emmanuel Tumusiime-Mutebile admits managing the revenue will be "a challenge" and that his country needs to "strengthen its institutions" ahead of pumping the oil that was discovered along its border with the Democratic Republic of the Congo in 2006.

In a salutary example, rather than saving or investing the tax revenue on recent oil transactions, the government used the money to fund Russian fighter jets to defend Uganda's border. The central bank was obliged to fund the controversial $720m purchase ahead of the anticipated tax revenues coming in and Mutebile says he has only been paid back half the money so far. Elsewhere, the World Bank helped Chad set up a fund, but instead of saving money for education and health, the government used it to buy arms.

In Nigeria, where institutions are much more robust than Uganda, saving oil revenue is still a slippery business. At its height Nigeria's ECA, set up in 2003, in which the government saves any revenue above a benchmark price set each year in the budget, reached about $40bn. It's valued at around $6bn today after being raided to fund the election.

The episode also went to show how political change thwarts even the best-laid plans to save. In 2003 finance minister Ngozi Okonjo-Iweala turned Nigeria's budget around, but her removal from the post - although she's back in office now - saw the savings slip away. Nigeria's other problem is that oil revenue snakes its way through the state-owned Nigerian National Petroleum Corporation before it ends up in central bank coffers. As a result, a fair bit is siphoned off en route.

"The NNPC has been known to under-report its oil revenues," says Kayode Akindele, a partner at Lagos advisory firm 46 Parallels. Like the ECA, the NNPC is also vulnerable around election time. "Money can be used without ringing alarm bells. It is seen as a cash cow," he says.

SWFs have a reputation for being opaque; more so in autocratic regimes. Only a handful of African countries willingly divulge their books. It makes gauging the extent of savings and the number of funds difficult but, as the continent finds itself in a better place financially than ever before, more countries are starting to save. A decade ago any discussion on sovereign wealth would have focused on OECD countries. Now the world's wealth has tipped in Africa's favour. It puts paid to that old adage that Africans kill the cow but the West steals the milk.