What's the difference between a 13D and a 13G?

Both report a stake of over 5% of a company. A 13D is for investors that may try to influence the company and is due within 5 business days; a 13G is for passive investors and institutions, is shorter, and can come later.

Schedule 13DSchedule 13G
WhoInvestors who may seek to influence or control the company (activists)Passive investors, and institutions buying in the normal course of business
First filingWithin 5 business days of crossing 5%Within 5 business days (passive investors) to 45 days after the quarter (institutions)
ChangesWithin 2 business days of a material changeWithin 45 days after the quarter of the change
DetailPurpose and plans, sources of funds, agreements with othersOwnership only

For investors, a 13D is usually the more interesting of the two: it can signal a campaign to change the company, and it comes quickly.

Related pages: Hedge Fund Tracker