There have been so many factors influencing the market's twists and turns now that it's easy to lose count.
Let's, however, take a look at seven that seem to be the most prevalent influences of the rapid-fire price action lately.
1. Price discovery
The notion that the marketplace actually can find a rational price, absent the influence of meddling central bankers, seems almost quaint. But we could be in the beginning stages of true price discovery as the Federal Reserve keeps the monetary printing presses shut down and prepares, at some point, to normalize interest rates.
Following the market correction that put the 12.5 percent off its 52-week high, the index's price-earnings ratio has fallen into line with historical norms near 16. In short, the market may finally have come to grips with the notion that in an economy struggling to grow more than 2 percent, a multiple of 18 is a little expensive.
Couple that with a market that hasn't corrected in nearly four years, and you've got some key ingredients for volatility.
"What I think we're seeing is a typical late-stage bull market in which there are precious few shock absorbers for the market to withstand even a modest negative impact," said Scott Clemons, chief investment strategist at Brown Brothers Harriman. "When something happens, the market reaction is going to be magnified."
2. The Fed
Fed actions seem like low-hanging fruit at this point, but the logic is hard to dispute.
The S&P 500 had gained more than 7 percent from Jan. 1, 2014, until Oct. 29, which was the day the U.S. central bank ended the third round of quantitative easing, a monthly bond-buying program that swelled the Fed's balance sheet to $4.5 trillion and jacked up the stock market index by nearly 200 percent.
Since the end of QE3? The market's down about 4 percent. Pretty simple, maybe too simple, but hard to ignore.
China's economy is in flux, and central planners are desperately trying to use policy to soothe market fears that the nation is heading into a deep and prolonged slowdown.
In keeping with point No. 1 here, China spooked a fragile market that might, at less lofty valuations, have been able to withstand a growth shock to the world's second-largest economy.
"Recent developments in China simply catalyzed a much-needed and overdue valuation correction in the U.S. stock market," S&P Capital IQ analysts Michael G. Thompson and Robert A. Kaiser said in a note. "To be sure, investors need to be concerned with market liquidity issues, anticipated corporate earnings growth and China's economy, but the market correction witnessed this past week was a necessary valuation correction that simply needed a catalyst."
What China leads to on a longer-term basis is hard to gauge, though some perspective is probably in order.
"The real broader view here is this is a natural correction in a broader bull market, not indicative of a broader recession," Liz Ann Sonders, chief investment strategist at Charles Schwab, said in an interview. "In terms of the averages, we've had much sharper corrections inside the market at the industry level, the individual company level. You can't just look at what the averages are telling you."