How to know/track the owners of a public company

How to know/track the owners of a public company and how can we know how things changed in any unit time - say 3 month period. This info is available in different places. How to compile them to know the dynamics.

Possible source of info are

1. SEC filing for the company.
2. Institutional Holders and Mutual Funds Holders periodic reports
3. Company's annual report
4. Sell/Buy raters will tell their hand if they hold any (This is not as reliable and we can not hold them accountable)
5. Press who cover the company

What can we learn when this is done methodically:

1. Find Insider trading, if any
2. Trends - just follow another knowledgeable person/company who do the research
3. We can get some indication on the internal health of the company

Example: http://sec.gov/Archives/edgar/data/789019/000119309911000056/xslF345X03/edgar.xml indicates this director got paid $10K (cash equivalent) + stocks - probably for attending a board meeting.