RogerScott

It's Not So Easy to Know What Buffett Is Buying

Also, Berkshire sometimes asks SEC to defer the required notice of holdings and sometimes SEC consents. Therefore, watchers of SEC filings sometimes assume BRK has sold a holding when actually it is buying more.
A likely signal that Simpson is behind a holding is to look at which subisidiary owns the stock. Simpson manages the GEICO portfolio.
Sometimes BRK buys a stock because of opportunities caused by a pending spin off. Do your independent research.
Simpson in the past decade or so has been a better stock picker than Buffett, according to Buffett.