Measured in dollars, Brazil's stock market has rebounded 164% since its lows of last November. I've highlighted this chart several times in the past, remarking that the outlook for emerging market debt and equity was very promising. So far that advice has been spot on. One key to the emerging market economies' recovery is easy money. Easy money helps push commodity prices higher, and it helps weaken the dollar. Both of these result in a big rise in cash flows for these economies.
Another factor is that they suffered terribly in the crash last year, so their rebound should be stronger. Yet another, which is relatively unremarked, is that for the most part these economies enjoyed better monetary policy than the U.S. did in the years leading up to the crash. Most emerging market currencies appreciated significantly relative to the dollar because of better monetary policy. Without the easy money-goosed speculation in real estate markets, their economies weren't so damaged in the crash. They suffered mostly from a big drop in commodity prices, but that problem has faded fairly rapidly with the return of easy money.
Finally, I would say that one reason these economies had better monetary policy was because they have managed (with some exceptions, notably Argentina) to mature at the fiscal policy level. Policies have been generally more stable and more respectful of the power of free markets than they have been in the past. When you introduce stability and maturity to an economy that has struggled for years only to keep falling behind the progress in the industrialized world, you have the potential for some spectacular growth catch-up, and that is what we are seeing now.
Full disclosure: I am long EMD, CHN, and SLAFX at the time of this writing.