--- title: "Concentrated vs. Broad Whale Books: How Five Giant Filers Approached Q4 2025" type: research slug: concentrated-vs-broad-whale-books-how-five-giant-filers-approached-q4-2025 canonical_url: https://13finsight.com/research/concentrated-vs-broad-whale-books-how-five-giant-filers-approached-q4-2025 published_at: 2026-04-29T09:35:28.358Z updated_at: 2026-04-29T09:35:31.131Z author: Marcus Chen author_title: Senior Market Analyst author_url: https://13finsight.com/authors/marcus-chen word_count: 675 locale: en source: 13F Insight --- # Concentrated vs. Broad Whale Books: How Five Giant Filers Approached Q4 2025 > A five-filer comparison shows why Berkshire looked like a conviction allocator while the giant diversified managers kept much broader top books in 2025Q4. The cleanest research question in 2025Q4 is not which mega-fund was biggest. It is which mega-fund was willing to let conviction show. Put Berkshire Hathaway, Capital World Investors, Capital International Investors, Wellington Management Group and Capital Research Global Investors side by side, and a sharp contrast appears immediately. Berkshire ran a capital-allocation statement. The others ran giant but much broader institutional books. Most concentrated: Berkshire put 70.9% of its filing into five stocks.Broadest top book: Capital World's top five were only 19.8% of its $735.30B filing.Tightest diversified manager: Capital Research Global reached 26.7% in its top five.Broadcom's role: AVGO led both Capital World and Capital International.Nvidia's role: NVDA led Wellington but still stayed below 5% of capital.Best comparative lesson: size and concentration are not the same thing. The Big Divide In 2025Q4Berkshire's filing is easy to summarize because it is built to be summarized. Apple, American Express, Bank of America, Coca-Cola and Chevron together made up 70.9% of disclosed value. That is what conviction looks like when a manager is comfortable letting a few decisions dominate results. The other four giant filers tell a different story. Capital World's top five totaled only 19.8%. Wellington's were 19.6%. Capital International came in at 24.1%. Capital Research Global was the most directional among the diversified cohort at 26.7%, but even that is nowhere near Berkshire's concentration profile. The implication is straightforward: investors should stop assuming every huge filer is making the same kind of portfolio statement just because the AUM number is large. What Top-1 Weight Says About StyleThe largest single position is another fast way to read style. Berkshire's top holding, Apple, was 22.6% of the book. That is massive. By contrast, the largest holdings at Capital World, Capital International, Wellington and Capital Research Global ranged from 4.9% to 7.7%. Those are important weights, but they still imply risk budgets designed to spread responsibility across a larger leadership cluster. That distinction is exactly why readers should compare Broadcom, Nvidia and Microsoft across multiple filers instead of reading one top position in isolation. In Berkshire, one position can define the story. In the diversified managers, a group of platform and infrastructure leaders usually defines it together. Scale Does Not Tell You ConvictionCapital World had the largest reported 13F AUM in this comparison at $735.30B. Capital International followed at $637.97B. Wellington and Capital Research Global were also above $500B. Berkshire was the smallest of the five by AUM at $274.16B. But the smallest filer by AUM was the strongest filer by concentration. That is the key analytical point. Too many 13F readers conflate scale with decisiveness. These five books show why that is wrong. The question is not who had the most money. The question is how much of that money the manager was willing to place behind a narrow front line. Berkshire answered with a resounding yes. Capital World and Wellington answered with breadth. Capital Research Global split the difference by keeping a more directional top tier without abandoning diversified-manager discipline. How To Use This On 13F InsightIf you want pure concentration, start with Berkshire. If you want a broad quality screen, start with Capital World or Wellington. If you want a middle ground where a giant manager still lets a four- or five-name core speak loudly, Capital Research Global is the cleaner next stop. Capital International sits somewhere in between, especially with its visible Apple increase beneath a Broadcom-led top line. This is also a reminder that stock-level overlap does not mean portfolio-style overlap. Multiple managers can own AVGO, MSFT or NVDA and still build very different books around them. That is why comparing concentration, top-1 weight and top-5 weight matters as much as comparing the stocks themselves. Questions Investors Should Ask NextWhich filer looked most like a classic concentrated allocator?Berkshire, by a wide margin.Which giant manager stayed broadest?Capital World Investors had the broadest top-book profile in this five-filer comparison.Why does this comparison matter?Because it shows that shared mega-cap ownership can sit inside radically different portfolio structures, and those structures change the meaning of the holdings list. ## FAQ ### Which filer was most concentrated in 2025Q4? Berkshire Hathaway was the most concentrated, with 70.9% of its filing in five stocks. ### Which filer had the broadest top-book profile? Capital World Investors had the broadest top five, at 19.8% of its filing. ### Does larger AUM always mean higher concentration? No. In this comparison the largest filer by AUM was not the most concentrated, and the smallest was the most concentrated. ### Why compare top-five weight across filers? Top-five weight is one of the fastest ways to see whether a manager is expressing broad exposure or concentrated conviction. --- Source: 13F Insight — https://13finsight.com/research/concentrated-vs-broad-whale-books-how-five-giant-filers-approached-q4-2025 Author: Marcus Chen — https://13finsight.com/authors/marcus-chen Last updated: 2026-04-29T09:35:31.131Z