days used to be when oil moved over $100 equities would be weak. traders used to be concerned about pressure on consumers. i'm not sure the algos care one way or the other.
some folks may think i'm harping by talking about HFTs so much, but this is a brand new paradigm. if emotion is out of the equation, the markets won't trade on fear or greed. at least not when we think they will, like when support is violated, etc.
we also don't know the extent to which HFTs collude with each other, or with government, to further distort market activity.