We appreciate the wonderful charts of Bespoke Invest, which we frequently feature here.
Although in some instances, they'd seem a bit bias (especially against China).
From Bespoke, ``One of the easy ways to see how a country is performing relative to other countries is to look at its market cap as a percentage of world market cap. In the early stages of the global rebound off of the March lows, the US rose significantly, but other countries were gaining even more. In recent months, however, the tide has turned, and the US is now outperforming the rest of the world. As shown, US stock market cap as a percentage of world market cap has been steadily rising since last November. During the 2003-2007 bull market, emerging markets and other countries really outperformed the US. If this bull market continues and the US continues to gain share, it will represent a very big trend change that will make a huge impact on portfolio performance depending on an investor's domestic versus international equity allocation." 
Nevertheless, this observation is true for today, according to Livemint,
``Funds are being rotated to the US—a fact corroborated by EPFR Global’s report that flows into US equity funds have been positive for four straight weeks, their longest winning streak since the third quarter of 2008. The paring of overweight positions not only protects against the risk of a sharp pullback, but also leaves the door open for positive surprises."
The reason China has been down is that she has been deliberately attempting to fight her "inner" devils (a.k.a bubbles).
In contrast, the US still is in an "inflationary" mode.
To add, last year saw emerging markets including China massively outperform the US, which is the reason why the US share of global market cap declined materially.
The recent outperformance of the US relative to emerging markets seems more of hiatus than of a "longer trend".
The axiom, "no trend moves in a straight line" for emerging markets should apply here.
Besides, it is also observable that the outperformance of the US has been in sync with the strength of the US dollar index (perhaps to reflect on the fund flows).
As the US equity markets regained their share of the global market cap beginning last November, the US dollar firmed as well.
But this can be interpreted differently, the vitality of the US dollar index isn't because the USD has been technically or economically "strong", but in the instance where both the US dollar and the euro (which weighs 57.6% in the US dollar index basket) have been weak, the euro has been relatively weaker than the US, ergo the strength of the US dollar. And this is why commodities have remained resilient even in the face of a strong US dollar (where is the US dollar carry?).
This also implies that the current trends isn't likely to last because of the problems that continues to ail the US. The relative strength especially applies to Asian and emerging market currencies.
This will be amplified if the oversold euro will see a sharp bounce. And this should also be reflected on the rest of the global equity markets.
Hence, in contrast to the projection that fund flows to the US will be a long term trend that would extend US equity outperformance, we see this as a short term phenomenon. Enjoy them as it last.
Although in some instances, they'd seem a bit bias (especially against China).
From Bespoke, ``One of the easy ways to see how a country is performing relative to other countries is to look at its market cap as a percentage of world market cap. In the early stages of the global rebound off of the March lows, the US rose significantly, but other countries were gaining even more. In recent months, however, the tide has turned, and the US is now outperforming the rest of the world. As shown, US stock market cap as a percentage of world market cap has been steadily rising since last November. During the 2003-2007 bull market, emerging markets and other countries really outperformed the US. If this bull market continues and the US continues to gain share, it will represent a very big trend change that will make a huge impact on portfolio performance depending on an investor's domestic versus international equity allocation." 
Nevertheless, this observation is true for today, according to Livemint,``Funds are being rotated to the US—a fact corroborated by EPFR Global’s report that flows into US equity funds have been positive for four straight weeks, their longest winning streak since the third quarter of 2008. The paring of overweight positions not only protects against the risk of a sharp pullback, but also leaves the door open for positive surprises."
The reason China has been down is that she has been deliberately attempting to fight her "inner" devils (a.k.a bubbles).
In contrast, the US still is in an "inflationary" mode.
To add, last year saw emerging markets including China massively outperform the US, which is the reason why the US share of global market cap declined materially.
The recent outperformance of the US relative to emerging markets seems more of hiatus than of a "longer trend".
The axiom, "no trend moves in a straight line" for emerging markets should apply here.
Besides, it is also observable that the outperformance of the US has been in sync with the strength of the US dollar index (perhaps to reflect on the fund flows).As the US equity markets regained their share of the global market cap beginning last November, the US dollar firmed as well.
But this can be interpreted differently, the vitality of the US dollar index isn't because the USD has been technically or economically "strong", but in the instance where both the US dollar and the euro (which weighs 57.6% in the US dollar index basket) have been weak, the euro has been relatively weaker than the US, ergo the strength of the US dollar. And this is why commodities have remained resilient even in the face of a strong US dollar (where is the US dollar carry?).
This also implies that the current trends isn't likely to last because of the problems that continues to ail the US. The relative strength especially applies to Asian and emerging market currencies.
This will be amplified if the oversold euro will see a sharp bounce. And this should also be reflected on the rest of the global equity markets.
Hence, in contrast to the projection that fund flows to the US will be a long term trend that would extend US equity outperformance, we see this as a short term phenomenon. Enjoy them as it last.
