Interesting article:Read more:...

Interesting article:
Read more: http://www.smh.com.au/business/inching-closer-to-a-less-stable-market-20110928-1kxgy.html#ixzz1ZJCGHPGl

An extract:
The HFT industry is a surprisingly tight community. Getco, Citadel Investment Group and Jump Trading are three of the biggest players, as are the prime broking platforms provided by groups including Deutsche, Morgan Stanley, JPMorgan and Nomura that they use. But its already powerful, accounting for about 25 per cent of global foreign exchange volume.

25% of global foreign exchange volume .... that is huge! They don't give figures for stocks but I have heard figures of around 50% of US stock volume on certain days. Now someone tell me that this is good for the market!