43 out of 45 global markets are oversold, according to BAML's "Breadth Buy" indicator. These extreme signals tend to be followed by a short-term 6-7% bounce, but, cautions chief investment strategist Michael Hartnett, a sustained rally would require a shift in policy behavior. What's more, the 2 markets not in oversold territory are the U.S. (SPY) and Japan (EWJ, DXJ) and they're kind of important. Most oversold: Brazil (EWZ), Turkey (TUR), South Africa (EZA), Mexico (EWW), Materials (XLB), China (FXI, CAF). Least oversold (in addition to the U.S. and Japan): Health Care (XLV, IYH), and Consumer Discretionary (XLY).