I want to invest like Warren Buffett. Who doesn't? To understand how he invests, I have purchased and read every book ever written on the man. A good starting point. The problem is that they all talk about the same few investments (e.g., Coca-Cola, American Express, GEICO). The no-brainer type investments. What else has he dabbled in?
See for yourself with the EDGAR database.
Investors like Warren Buffett (via Berkshire Hathaway) must file a quarterly report with the SEC disclosing their holdings at that time. Such filing is done on Form 13F or 13F-HR (Form SC 13G for money managers like Pabrai Funds or for Buffett personally). On that report, they list the stocks they hold and the number of shares. For example, on its February 14, 2008 amendment to Form 13F-HR, Berkshire reported holding $2.4 billion of Kraft Foods, or 69.6 million shares.
There are a zillion websites out there making that purchase big news, but it is not super-helpful from a "I want to understand his past purchases" perspective. For that, we turn to EDGAR.
First, Get Yourself To Berkshire
In the EDGAR Database Primer, we took a look at how to get on EDGAR and find a company's filings. Let's take it a step further. First, we head over to the EDGAR search screen and search by company name. I'll put "Berkshire" in and see what happens:
There are a ton of results for Berkshire (in alphabetical order), so we need to scroll down a bit to find Buffett's company — Berkshire Hathaway Inc. To the left of the company name is the CIK (Central Index Key), a unique company identifier for filing with the SEC. Clicking that CIK number  will take us to Berkshire's filings.
Having clicked the CIK, we come to a somewhat (now) familiar screen — the list of all of Berkshire's filings. For our purposes here, we don't need to see the letters from the SEC, the Form 4s, or other filings — just the Form 13F-HR and any amendments. We'll use another search box, this time found in the top right of the page we are on.
Narrow The Results
We want to search for Form 13F-HR (amendments will automatically be included) and we want to see 100 results per page. Because we are requesting a specific form, we can ignore the "Ownership" selection because ownership forms (3, 4, etc) won't appear anyways.
Hit Retrieve Selected Filings and there you have it — every Form 13F-HR and amendment for Berkshire Hathaway leading back to May 15, 1999. You can now see every purchase or sale Berkshire disclosed and then start ripping apart those investments.
Understanding Form 13F-HR
As we look at this Form 13F-HR filed on Feb. 14, 2001, we can peak at Berkshire's portfolio (save any investments he was then making for which he filed for confidentiality and later disclosed on a 13F-HR/A). At that time, he held 7,697,500 shares of H&R Block, a position he increased by 2.4% over the next three months, as can be seen by this Form 13F-HR filed on May 5, 2001.
Using Form 13F-HR For Your Own Research
What was happening during those three months that Berkshire was buying? What was attractive about H&R Block back in 2001 and why did Buffett start selling it last year? What else can you learn from Buffett and others?
The 13F-HR is not the prettiest form in the world and a number of websites track these "guru" purchases and sales; still, it is a heck of a place to do your own research and look into the past to help you invest for the future.