Interesting plot showing the share of algorithmic trading in each asset class. I wonder if it's a coincidence that a lot of banks have downsized equities first, then futures, while now bonds and mortgages are hot hot hot. Perhaps when machines take over, the margins are too slim to matter even for the big guys. May be HFT is becoming more of a niche method for medium to smaller funds, much like trend following is now mostly a retailers game (i.e., there is still money in it, but not enough to attract the biggest players).