13-F (Institutional Ownership)

• Reports equity holdings by institutional investors (mutual funds, banks, corporations, & others)
• Filed within 45 days of the end of each quarter of the fiscal year

 
13-D (5% Ownership)

• Reports holdings of 5% or more of a corporation’s shares
• Can signal a merger or increased shareholder activism
• Filed within 10 days of the event

Forms 3, 4, 5 (Beneficial Ownership)

• Reports insider ownership by officers and directors
• Initial purchase (Form 3), Change in holdings (Form 4) and Annual filings (Form 5)
• Called a “Section 16” filing

Companies include a year-end summary of shares owned by benefical owners, directors, management and executive officers in their 10-K report, Item 12.

Insiders

Corporate insiders are the company's officers and directors, and any beneficial owners of more than ten percent of a class of the company's shares.

Institutional Owners

13F institutions are investment managers that invest in their own account or manage the accounts of other investors and have authority over assets in excess of $100 million.  Institutional investment managers can include banks, investment advisors, insurance companies, broker-dealers, mutual funds and pension funds.