shareholder changes, page-18

A change in substantial holder notice should be issued when the percentage of the company held changes by more than 1 percent from the previous notice. This equates to about 1 mil shares in AHS.
Hence I hope to see another notice soon after the 810,000 cross trade.

If insiders are trading, they may be doing it in small volumes so they dont move the price too much.
Its only when a large number of buyers get some info, or find out without much time left to buy that they push the price and volume up alot.