Best way to follow major shareholders' activity?

[Mustardeer]

Meaning what's the easiest/most accurate source to type in a stock's name and find out the activity of the top shareholders? For example investor A who owns a ton of shares bought ( or sold ) x amount of shares on this date.

 

[Mustardeer]

Thanks Peter, Finviz does have an Insider Trading tab but it just lists investors and their transactions. Not what I'm looking for. If I search say for AMZN there are 2 insider buttons but nothing happens when I click on them ( I registered with Finviz too ). Is there a better website for this? My broker is Merrill Lynch by the way.