The unrecognized reason emerging markets are getting crushed is because corporate earnings in those regions are declining, most likely because of rising labor costs, according to economist Ed Yardeni, president and CEO of Yardeni Research.

The forward earnings of the MSCI Emerging Markets composite peaked in August 2011 and have trended lower since then, Yardeni observed in his blog.

He said analysts' consensus estimates for emerging markets for 2013 and 2014 also are declining, and at a faster pace in recent weeks. Net earnings revisions have been negative for the past 30 months.

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"The big story is the collapse of the forward profit margin since early 2011 from around 8.5 percent to 6.5 percent now," Yardeni wrote.

"The likely cause of that is rising labor costs. The recent rise in oil prices must also be squeezing margins."

Yardeni said Wall Street is focusing primarily on fear that the consequences of Federal Reserve tapering will be more severe for emerging markets than for developed nations, but that investors must also recognize the declining profits picture.

Quartz, however, had a different take on the state of emerging markets. It said that for the first time, the combined gross domestic product (GDP) of emerging markets has apparently eclipsed that of the developed world in 2013.

An International Monetary Fund (IMF) analysis found that advanced economies will have a purchasing price parity-adjusted GDP of $42.8 trillion in 2013, while that of emerging economies will be $44.4 trillion.

By the IMF's definition, advanced economies are the 34 countries that result from combining the members of the G7, euro area countries and the four "newly industrialized Asian economies"—Taiwan, Hong Kong, Singapore and South Korea. The world's 150 other nations — including China — are considered emerging or developing.

"It's worth keeping in mind that the emerging economies have strength in numbers. Not only are there more emerging and developing nations; those nations also boast a larger combined population," Quartz said.

Developed nations are still far ahead of emerging markets on a per-capita income basis, Quartz noted. The aggregate per-capita PPP-adjusted GDP in emerging nations is $7,415, while the same measure for advanced economies is far higher at $41,369.

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