We can't really be sure how much input Mr. Buffett had on various equity investments. Someone else may well have been the primary advocate for particular investments. Those investments may have been their idea and based on their research and expectations.
But I suspect that Mr. Buffett, at the least, has signed off on any major equity investments. He - as Warren Buffett, not as Berkshire Hathaway - is listed on the (SEC Form) 13Fs as one of the institutional investment managers in connection with all of Berkshire Hathaway's Apple holdings just as he is for all of Berkshire Hathaway's 13F holdings. Other institutional investment managers (i.e. other entities, all of which are companies rather than natural persons) are listed in connection with most of those holdings, but they are listed in addition to Mr. Buffett not in place of him.
If you google around a bit, the way Warren Buffett structures his lieutenants' investments is that each of the 2 has 9 billions to invest on their own, without needing WB's consent or input. Their investment picks are listed under his name by design so we can't really tell who actually made the investments. As pointed out by a recent article, his lieutenants' investments sometimes influence WF's investments but they are rare (Precision Cast Parts)
Most of us already know that WB wasn't the one that initiated the original purchase of AAPL in the beginning of 2016. The first purchases were done by one of his investment manager and that is common knowledge. But do you, or anybody else, know for sure that WB wasn't personally involved in the quadrupling of Berkshire Hathaway shares of AAPL in the fourth quarter (of 2016)?
The initial purchase was about 17% of the investment manager $9B allowance. Which don't seem out of place. If he made no other investment by the 4th quarter, the quadrupling of his AAPL shares would be mean he invested more the 50% of his remaining allowance in one stock. I would think that WB might have some sort of say if one of his investment manager wants to invest more than 60%% of his $9B allowance in just one stock. Or it was WB himself, that increased BH shares of AAPL in the 4th quarter.
Agreed that it's an unknown at this point whether WB wasn't the one who bought the additional Apple shares. However, chances are that he wasn't. I for one hope that he was though. It's not true that most people know about these details because the media headlines almost always say WB bought Apple shares, event the initial ones.
I don't think anyone (here) is disputing that others at Berkshire Hathaway make equity investment decisions - that they, e.g., in effect have their own investment accounts which they use to make investments on behalf of Berkshire Hathaway. I also don't think that anyone (here) is disputing that the original decision to invest in Apple was not Mr. Buffett's, at least that he wasn't the main impetus behind it.
But we don't know how much of a role he played in the decisions to continue buying Apple. We do know (from Berkshire's 13Fs) that for one block of Berkshire's AAPL holdings he was the only listed institutional investment manager. That means that no other natural person had investment discretion over that investment. Further, Charlie Munger has referred to Mr. Buffett buying Apple. He did that in pointing out that Mr. Buffett, as well as Mr. Munger himself, have changed. So it seems that some of the Apple investment was Mr. Buffett's decision, that he at least played some role in those Berkshire investments.
When Mr. Munger referred to Mr. Buffett buying Apple, did he just mean in the sense that Mr. Buffett is the boss at Berkshire and Berkshire has bought Apple? Perhaps, but that's the characterization that Mr. Munger used - to the effect that Mr Buffett bought Apple. So I don't think it's necessarily misleading for others to refer to Mr. Buffett buying Apple. At the very least he has investment discretion over Berkshire's Apple investments just as he does over all of Berkshire's equity investments, regardless of whether he used that discretion in particular instances - regardless of whether it was someone else that was deciding what to buy or sell in particular instances.
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But we don't know how much of a role he played in the decisions to continue buying Apple. We do know (from Berkshire's 13Fs) that for one block of Berkshire's AAPL holdings he was the only listed institutional investment manager. That means that no other natural person had investment discretion over that investment. Further, Charlie Munger has referred to Mr. Buffett buying Apple. He did that in pointing out that Mr. Buffett, as well as Mr. Munger himself, have changed. So it seems that some of the Apple investment was Mr. Buffett's decision, that he at least played some role in those Berkshire investments.
When Mr. Munger referred to Mr. Buffett buying Apple, did he just mean in the sense that Mr. Buffett is the boss at Berkshire and Berkshire has bought Apple? Perhaps, but that's the characterization that Mr. Munger used - to the effect that Mr Buffett bought Apple. So I don't think it's necessarily misleading for others to refer to Mr. Buffett buying Apple. At the very least he has investment discretion over Berkshire's Apple investments just as he does over all of Berkshire's equity investments, regardless of whether he used that discretion in particular instances - regardless of whether it was someone else that was deciding what to buy or sell in particular instances.