Lou Simpson was investing a much smaller amount than T&T and yet both his trades and his overall record were able to be viewed by shareholders. Today that type of info is treated as classified information.

They were both disclosed in the same required way on the 13f forms, specifically in the same minimal way required by law. Unless I am greatly mistaken, it just so happened that Mr Simpson worked for a different legal entity within the group, so his trades could be identified that way.

As far as I know, the only reduction in the amount of information disclosed is that the annual report no longer includes a list of the top ten equity holdings with their share counts and cost basis prices. I suspect that one reason is that Berkshire became so big that, other than a couple of positions which were discussed like Apple, the firm was no longer primarily an equity holding company and individual stock positions were no longer very material to understanding the progress of the business. With few exceptions one can look at it as merely a portfolio, especially as it's no longer likely that superior stock picking will make much difference to returns over time.

As an aside, bear in mind that the purpose of the 13f is not so the public can see what investment managers are doing. It's so the SEC can know who has control of company shares. The fact that it allows people to be copycats is a side effect.

Jim