Every 13F on file since Q2 2013: what William Von Mueffling bought, added to, reduced and sold each quarter, largest moves first, with share counts adjusted for stock splits.
Each quarter is compared with the one before it. A quarter whose predecessor has no filing on file shows the book's size and no moves. Moves are ranked by the dollars that changed, at that quarter's reported prices; the twelve largest are kept.
Source: the manager's Form 13F-HR on SEC EDGAR, kept as immutable quarterly snapshots; changes compare two consecutive filings. A 13F is filed up to 45 days after quarter end and covers US-listed long positions only. Tickers come from a self-maintained CUSIP map; a position without one shows its CUSIP. Method notes in where the numbers come from.