China definitively announcing an end to tightening and/or offering up stimulus could bolster SPDR Metals and Mining ( XME) as well as Australia ( EWA) and South Africa ( EZA). A pleasant trajectory in the upcoming employment data may boost Vanguard Consumer Discretionary ( VCR). 3. Profit-Taking and Tax-Loss Harvesting. Even as the S&P 500 rocketed 3.4% in the singular Thursday session, volume was only average for the S&P 500 SPDR Trust ( SPY). In fact, institutional investors sold $521,000,000 of SPY into the day's strength. Considering the sheer size and scope of SPY, this isn't a monstrous hit to the net assets. Nor would I regard it as a bearish sign. However, it may indicate a high level of interest in taking profits. It should also give folks reason to expect a higher-than-normal amount of volatility for November and December, as there will be plenty of investors needing to harvest their 2011 tax losses.