These days, real excitement isn't in the stock market.
While sharp intraday moves in the S&P 500 have become more common of late, overall volatility has remained low. Meanwhile, big swings in bonds, commodities, and especially currencies are running rampant.
Over the course of 2015, the popular oil ETF USO has experience 3½ times the daily volatility of the SPDR S&P 500 ETF (SPY). And bonds haven't been quiet, either—the Barclays bond ETF (TLT) has experienced 25 percent greater daily historical volatility than the SPY.
For Stacey Gilbert, head of derivative strategy with Susquehanna Financial Group, the explanation is simple. Recently, all markets have been responding to central banks, as Europe embarks on new easy money policies, and the Federal Reserve makes slow-motion (but not "patient") gestures toward eventually raising short-term rates. But some asset classes are more unified in their response to central bank moves.
The generally strong U.S. dollar "is great for some companies, not great for others. So therefore, you have a little bit of diversification in the stock markets," Gilbert said.
Meanwhile, expectations about central bank actions and inflation are critical for fixed income investors. And commodities often move inversely to the dollar, given that as each dollar becomes worth more, it should take fewer of them to buy the same amount of goods.
The currency volatility certainly showed no signs of abating on Wednesday. As the Fed presented a move dovish statement than expected, the US dollar index fell as much as 3 percent, a gigantic move for a currency, especially after marching in a seemingly indomitable path higher over the last eight months.