For investors around the world, 2015 is turning into a year to forget. Stocks, commodities and currency funds are all in the red, and even the measly gains in bonds are being wiped out by what little inflation there is in the global economy.

Rounding out its steepest quarterly descent in four years, the MSCI All Country World Index of shares is down 6.6 per cent this year, including dividends.

The Bloomberg Commodity Index has slumped 16 per cent, while a Parker Global Strategies index of currency funds has dropped 1.8 per cent. Fixed income has failed to offer much of a haven: Bank of America's (BOA) global debt index gained just 1 per cent, less than the 2.5 per cent increase in world consumer prices shown in an International Monetary Fund index.

After three years in a virtuous cycle of rising share prices and unprecedented monetary easing, markets are now sinking as emerging economies from China to Brazil weaken and corporate profits slump. Analysts have cut their global-growth estimates for this year to 3 per cent, from 3.5 per cent at the start of the year, and the turmoil has added pressure on central banks to prolong their stimulus programmes, with traders scaling back forecasts for a Federal Reserve interest rate increase by year-end.

"There was an element of people believing they had found some sort of holy grail of investing, then this breakdown occurs and it breaks down in a way that is remarkable," said Mr Tobias Levkovich, Citigroup's chief United States equity strategist. "What seemed to trigger this all was China. It sent us on a wave of downward fears."

China's official factory gauge stabilised last month, adding to speculation that government stimulus measures are heading off a slump in manufacturing.

Investors suffered the brunt of this year's losses in the third quarter. MSCI's global equity index sank about 10 per cent in the period, while the Bloomberg commodity index lost 14 per cent in its biggest slump since the global financial crisis seven years ago.

The average level of BOA's Market Risk index, a measure of price swings in equities, rates, currencies and raw materials, was the highest this quarter since the end of 2011. The Chicago Board Options Exchange Volatility Index, a gauge of turbulence known as the VIX, reached levels in August not seen since 2011 .

China has been the biggest source of anxiety for investors, after turmoil in the nation's financial markets fuelled concern that the country's worst economic slowdown since 1990 was deepening.

The Shanghai Composite Index fell 29 per cent in the third quarter, the most worldwide, and the yuan weakened 2.4 per cent after authorities devalued the currency in August. That sent a shudder around the world.

MARKETS UNRAVEL

The worst quarter in seven years for the Bloomberg JP Morgan Asia Dollar Index, which tracks the region's 10 most-active currencies outside Japan, has pushed it down 5.1 per cent this year to the lowest levels since 2009. A similar measure for Latin American currencies tumbled to a new record.

Even those investors speculating on dollar strength have found trades upended by the yen's 2.2 per cent rally in the third quarter and a revitalised euro.

"This is going to go down as one of the worst quarters in a while," said Mr Michael Antonelli, an institutional equity sales trader at Robert W. Baird & Co. "It all kicked off from a China slowdown concern and has unravelled piece by piece."

In the US, the Standard & Poor's 500 Index has dropped about 7 per cent since the end of June as firms reported a 1.7 per cent slump in second-quarter earnings and cuts to analyst profit estimates outnumbered increases for 17 straight weeks.

Commodity producers are to blame for a big portion of those reductions after Brent crude oil fell below US$50 (S$72) a barrel on the highest output in seven years from the Organisation of Petroleum Exporting Countries.

Copper reached a six-year low, while platinum fell 15 per cent in the quarter. The precious metal, used in devices that curb harmful emissions from cars, bore the brunt of Volkswagen's attempts to rig pollution tests for US diesel engines. Glencore, the commodities group that has become a proxy for the industry's woes, plummeted 69 per cent year-to-date on the London Stock Exchange.

Credit markets have not been excluded from the losses. The BOA Merrill Lynch Global Corporate & High Yield Index is set for its first annual decline since 2008, with yields approaching the highest since 2012. Government bonds returned just 1.4 per cent amid strong demand for haven assets.

FED DILEMMA

For all the turbulence, the US economy is still "pretty solid" and the Fed should raise interest rates, said Mr Howard Marks, co-chairman of Oaktree Capital Group, whose firm is the world's biggest manager of distressed debt. A rate increase of 25 basis points, or a quarter of a percentage point, will not be "that big of an event" after the Fed held borrowing costs near zero on Sept 17, said Mr Marks.

The "phantom rate hike" last month has only added to market volatility, said Mr Tony Crescenzi at Pacific Investment Management.

Traders in the futures market have been pushing back forecasts for Fed lift-off. They are pricing in a 41 per cent probability that the Fed will raise its benchmark rate by a quarter-percentage point by the Dec 15-16 meeting, down from 60 per cent at the end of August.

The European Central Bank and the Bank of Japan have not ruled out extending their stimulus programmes, while forecasters, including HSBC Holdings, predict China will cut banks' reserve ratios to bolster economic growth.

"More and more people will expect the Fed to postpone tightening this year if these very fearful conditions continue," said Daiwa SB Investments money manager Kei Katayama.

For Mr Cristian Maggio, London-based head of emerging-markets research at Toronto Dominion Bank, a slide in developing-nation assets may not be over.

Stocks from emerging markets dropped the most in four years in the third quarter, while local currency sovereign bonds retreated about 3 per cent. Brazil's real tumbled to a record low last month as the nation's credit rating was cut to "junk" status by Standard & Poor's.

"(In the) longer term, we still see fundamental reasons for weakness," Mr Maggio said. "The sell-off looks overdone, and I expect this extreme pessimism to correct somewhat in the near term.

"But markets will have to believe that the sell-off of emerging market currencies has gone too far. Poor sentiment and panic selling can be self-fulfilling."

BLOOMBERG