The drops today were sudden and precipitous...characteristic of specialists pulling bids in an eyewink. The indexes would then labor upward for a few bars, and then get hit with another round of bid pulling. Neither technical trends nor fundamentals account for what is happening. It is a "quant" driven market. Any asset that gets out of line (currency, interest rates, volatility, gold...etc.) could trigger the next algorithm-driven move. This is very dangerous. One algorithm could start feeding on another and drive the whole thing into meltdown, or melt up, too, I suppose. I'm trying to stay ahead of it by keeping my delta slightly biased via adding/subtracting puts and calls as we reach (and cross) the outsides of trading ranges.