being mercilessly screwed down, page-41

Without having brokerage id attached to the trades, its very difficult to group the algo trades together to infer their intent.

You would need something like webiress so you can replay the days trades and watch when and how those trades get played out.

It could be that they are doing a TWAP or a VWAP order or something much more complex like a sniper, iceberg etc etc.

Some of the algo strategies out there do very perculiar things like having several buys and several sells open at the same time at all sorts of different prices for some index based strategies. They often use the low volumes to be able to make sure they have an order in the queue which is then sometimes amended/pulled/etc depending on some complex event processing.

Search for algorithmic trading on google and you will find some handy info.