This great graphic was composed on Bloomberg. It shows four stock indices' performance since the start of the year. It is indexed so that each index started the year at 100.
The yellow line is the Stoxx 600, a benchmark of European shares. It peaked a few days before the other markets, and has fallen the furthest since.
The fuchsia line is the MSCI Emerging Markets equity index. It peaked the same day as the S&P 500 (white line), but has held up the best and is still up 1.2% year-to-date.
The green line is the MSCI Asia Pacific Index. Today's 3.4% decline puts it about 0.3% lower year-to-date.
Of course, the chart is incomplete, insofar as today's action is not complete.
The S&P has been choppy, and is currently about 0.4% lower. Latin American markets may take a toll on the MSCI EM equity index. European markets are off their lows, but are also struggling to maintain any meaning upside momentum. US leadership may be awaited.