When investors thought that the Federal Reserve was going to stem the flow of easy money into the U.S. economy, it was emerging markets that sold off the most. Now that the "taper" is off, it's emerging markets that are on a tear.
When U.S. interest rates rise, they provide more competition against other assets with higher yields. But now that the Fed may be keeping pressure on long-term rates for longer than expected, that competition may disappear.
Markets and currencies in the Western Hemisphere moved in tandem with the U.S. markets yesterday—which is to say, a lot higher: the Brazilian Bovespa shot up 2.64 percent, and the Mexican Bolsa tacked on 1.86 percent.
Brazil's currency also rallied sharply, giving some relief to that country's Central Bank which has been intervening to defend the currency.
(Read more: Some emerging market stocks seen as 'dirt cheap')
Overnight markets in Southeast Asia rallied too. Indonesia climbed more than 4.5 percent. India & Thailand, more than 3 percent. The Indian Rupee and the Turkish Lira both hit one-month highs as well.