Ann: Intention to Make Takeover Bid, page-167

Simple.

Because brokers make use of computer-based algorithms when executing large institutional orders; for several reasons:

1. To not have undue influence on the share price, i.e., to maintain an orderly market
2. In an attempt to match VWAP
3. To not give proprietary order intel to other market participants

All perfectly plausible and legitimate.

For example, if a large institutional investor wanted to by or sell 100,000 TRS shares, how do you think the share price would respond if the broker was naive enough to place that order in the screen for all to see?

If you dealt in hundreds of millions of dollars of share trades every year, like major investment instos do, you too could become an institutional grade client of a stockbroker and you, too, could have your large orders executed via an algorithm.