Today the DJIA dropped 275 points and some media entities ascribed this to U.S. unemployment figures, also released today, particularly amid other ongoing news about European economic problems.
What I'd like to understand is: Whose news-driven sell-offs are causing such drops?
I ask because I can think of a number of classes of shareholders who wouldn't sell on such news. For example, I'd think that an appreciable part of the ownership of the DJIA are owned by the "average guy" who owns stocks as part of his 401k. My guess is he is not learning of U.S. unemployment figures or Spanish bank crises and then calling his fund manager and telling him to sell his holdings--I'd guess the average 401k holder is mostly oblivious to the financial world in this way (though he might panic sell at times like early 2009's bottom).
The same would go for "old fashioned" investors who buy large and well-known companies like IBM, trust in the market, and just hold it for many years while mostly not paying attention to the economic factors. Day, swing, and other technical traders for the most part just trade on chart patterns. Fundamental analysis traders trade mostly on individual companies' facts on paper.
So--if it really is news causing sell-offs (or buy-ins)--which sector of traders are reacting to the news so strongly and in such numbers as to cause such significant changes in the DJIA? (for example, today's drop wiped out all of 2012's gains)
I'd guess mostly large investment corporations, but also to some degree traders who pay attention to world events, but any elaboration that gives me a sense for the proportion of the market owned by "news-triggered and market-swinging" entities would be helpful.
This is in part a practical question in that I want to understand what to expect--if anything can be expected reliably--for my own enters/exits into the market given my read of world events.