Equities and stock exchange traded funds started the year in back-and-forth action, struggling to break above recent highs. However, soft economic data, coupled with troubles in the emerging markets, triggered a global sell-off in the last week of the month.

The Dow Jones Industrial Average declined 3.9%% over January. Meanwhile, the Nasdaq Composite dipped 0.8% and the S&P 500 fell 2.4%.

The top performing non-leveraged ETFs over January include iPath Dow Jones-UBS Natural Gas Total Return Sub-Index ETN (NYSEArca: GAZ) up 23.0%, PureFunds ISE Junior Silver ETF (NYSEArca: SILJ) up 22.7% and iPath Global Carbon ETN (NYSEArca: GRN) up 20.1%.

Natural gas prices have surged, breaking above $5 per million British thermal units this month, as Americans use the fuel to heat homes amid an arctic blast. [Obama, Weather Lift UNG; More Gains Seen]

Silver stocks strengthened after strong guidance numbers, and miners are expecting higher production numbers this year. Many silver companies are increasing production to help offset lower silver prices. [Silver ETFs Shine With Miners Taking Charge]

GRN tries to track the performance of the most liquid carbon related credit plans, including both the European Union Emission Trading Scheme and Kyoto Protocol’s Clean Development Mechanism. The carbon markets are strengthening after shrinking 38% in 2013 on low carbon targets, according to The Guardian.

The worst performing non-leveraged funds for the month include iShares MSCI Chile Capped ETF (NYSEArca: ECH) down 14.0%, Global X FTSE Colombia 20 ETF (NYSEArca: GXG) down 13.5% and Market Vectors Russia Small-Cap ETF (NYSEArca: RSXJ) down 13.3%.

January started off on uncertain footing, with enthusiasm over improving economic data tempered by the strong likelihood of Fed tapering. Moreover, weak fourth quarter earnings put selling pressure on the stock market.

With speculation of Fed tapering, emerging market currencies sold off, with notable drops in the Turkish Lira, Argentine peso and South African rand. [Tapering Bets Send EM Currencies Reeling]

Moreover, uncertainty over emerging market growth, notably in China, the second largest economy in the world, compounded pressure on equities.

So far, the stock market decline in January is looking like the worst since 2010.

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