Nearly correlating with the Yen's pull back from its negative trend breakout.
The market probably got an extra boost from Yellen's commitment to the current plan, but realistically the extra boost prob can from China. The FXI is either seeing a potental break from its negative trend or a head fake. (Strongly breaching the 14sma, only to continue downward.)
Frankly, the emerging market "threat" is bullshit. There are issues with the EM that will cause the EMs to underperform, but the underperformance will not take global GDP with it. The only real concern is how much pain the Chinese central government will allow the china banks and investors to swallow. This will then dictate how high the Yen will reach, and how low the SP500 can go.
The downside for the SP500 seems limited to around 1650 or the 14smaon the monthly.
The upside here seems limited too. Above 1800s, the trailing PE on the SP500 is above the historical highs. For the past couple of months the SP500 decided to trade with a multiple at and above 18 (via Reported EPS). Thats high. Below is a chart highlighting the market with its multiple high.
(Fundamentally, the downside will be limited because China will only allow a manageable level of pain. And the Bank of Japan will kick in its purchases (stimulus) to keep their economy humming.)
Update: SP500 estimates were revised, and they were an interesting leap forward. Standard and Poor's now have about a 20% eps growth. The new estimates, and with much of Q4 2013 reported, the market target price and trailing multiples were updated.
If the new estimates are to be realized, upside is not as capped as previously expected. Although the China issues are still very real.