4:15 pm : The major averages ended modestly lower with the S&P 500 shedding 0.3%.

The benchmark average saw an opening loss of 1.2% after Japan's Nikkei tumbled 7.3%. Japanese stocks sold off amid continued volatility in Japanese Government Bond futures as the 10-yr yield spiked almost 16 basis points to 1.002 before the Bank of Japan's JPY2 trillion liquidity injection caused yields to retrace their gains.

Adding insult to injury was news out of China where the HSBC Flash Manufacturing PMI (49.6 actual, 50.5 consensus, 50.4 prior) fell below 50 for the first time in seven months.

All ten sectors began the session with sharp losses before the daylong rebound helped some groups return to yesterday's closing levels.

The utilities sector was the weakest performer, ending lower by 0.8% after a morning flash crash in American Electric Power (AEP 48.28, -0.31) and NextEra Energy (NEE 78.22, -0.94) briefly wiped out more than $33 billion in combined market capitalization.

Meanwhile, other defensively-oriented sectors outperformed the broader market with the telecom space registering a gain.

Cyclical groups were mixed throughout the day as technology and materials made a brief appearance in positive territory.

In the tech sector, major components like Apple (AAPL 442.14, +0.79), Oracle (ORCL 34.23, +0.11), and Cisco Systems (CSCO 23.51, +0.17) held up relatively well while Hewlett-Packard (HPQ 24.86, +3.63) surged 17.2% following its earnings beat on below-consensus revenue. In addition, the computer company guided third quarter earnings above analyst expectations and raised its dividend 10.0% to

12:05AM Nikkei & S&P Futures Update : Japan's Nikkei Average just moved aggressively lower; Now through last night's 'Crash' lows... Currently trading at 14620, and just dropped nearly 400 points in about 5 minutes, but stabilizing a bit now.

S&P Futures are exactly Flat after hours, trading now at 1650.