An FMP Signals Lab Case Study
In the first quarter of 2026, Berkshire Hathaway more than tripled its position in Alphabet's Class A shares (GOOGL), lifting its stake from roughly 17.8 million to 54.2 million shares. Applying the 13F Drift Framework to the quarter shows this was active buying rather than a byproduct of price movement: GOOGL fell about 8% over the quarter, yet Berkshire's book weight in the name rose sharply, giving it the strongest drift score of any large filer in the set. That accumulation ran against a divided field, with several long-established holders, led by Wellington, reducing their positions over the same period. The case study applies the 13F Drift framework to a single contested ownership move to show how the active-versus-passive decomposition changes the read. It is not a forecast of Alphabet's returns.
Case Study Parameters
|
Signal |
13F Drift |
|
Company/Security |
Alphabet Class A shares (GOOGL) |
|
Quarter |
Q1 2026 |
|
Filing Window |
Quarter ended Mar. 31, 2026: filings due by May 15, 2026 |
|
Share Class Scope |
GOOGL only (does not include GOOG Class C shares) |
|
Methodology |
Active vs. passive decomposition from the 13F Drift Framework |
|
Universe/Filter |
All reporting 13F filers with disclosed GOOGL positions for the quarter |
|
Data Source |
FMP 13F institutional ownership analytics endpoints |
|
Data Pull Date |
June 30, 2026 |
New to the 13F Drift Framework? The full methodology, including the active-versus-passive decomposition and the reproducible code, lives on the framework page. This case study applies it to one name for one quarter.
What We Looked At
Alphabet was one of the most debated megacaps of the first quarter of 2026. The headline was Berkshire Hathaway, which more than tripled its position over the quarter. But a single filing only shows the endpoint, not whether the move was real conviction or an accounting artifact of price movement, and not whether other large managers agreed or leaned the other way. This case study runs the 13F Drift Framework on Alphabet's Class A shares (GOOGL) for the quarter ending March 31, 2026 (filed by the May 15 deadline) to separate active buying from passive drift and to see where the large holders actually stood.
Defining Scope For the Study
Alphabet trades under two tickers, GOOGL (Class A) and GOOG (Class C), and institutions report positions in each separately. This analysis covers the GOOGL line. Figures here are position changes in GOOGL specifically, not a filer's combined Alphabet exposure across both share classes.
Berkshire's Move Was Conviction, Not Drift
Berkshire increased its GOOGL share count by 204% over the quarter, from roughly 17.8 million shares to 54.2 million, adding about 36.4 million shares. The drift score combines the change in share count, the percentage change, and the trade-driven weight change into one number, where a higher score means stronger net accumulation. That opening figure alone is striking, but the drift framework makes it more so. GOOGL fell about 8% during the quarter (quarter-end close to quarter-end close, roughly $313 to $288), which means a manager who did nothing at all would have seen the position's weight in their book drift lower. Berkshire's book weight in GOOGL instead rose by 3.89 points. When the framework decomposes that move, the passive component (what price movement alone would have produced) is slightly negative at -0.17, and the active component (the trade-driven residual) is +4.06. In other words, essentially the entire weight increase came from buying, against a falling price. That is consistent with deliberate accumulation, and it produces the highest drift score in the defined GOOGL universe for the quarter, +4.20, more than triple the next filer.
Berkshire Hathaway: GOOGL Weight Change Decomposed, Q1 2026
Reading the chart: Total weight change is the reported change in GOOGL's share of Berkshire's book. Passive is the estimated effect from price movement alone. Active is the trade-driven residual, what remains once price movement is removed.
What the Accumulator Table Surfaces and What Needs Context
Top Active Accumulators of Alphabet, Q1 2026
|
Filer |
Share Change |
Pct Change |
Active Weight |
Drift Score |
|
Berkshire Hathaway |
+36,403,656 |
+204.0% |
+4.06 |
+4.20 |
|
SG Americas Securities |
+9,819,146 |
+126.5% |
+2.59 |
+1.26 |
|
Capital World Investors |
+11,465,200 |
+21.3% |
+0.46 |
+0.71 |
|
Arrowstreet Capital |
+8,112,680 |
+90.9% |
+1.15 |
+0.67 |
|
Value Aligned Research |
+6,370,900 |
+389.8% |
+6.39 |
+0.60 |
|
JPMorgan Chase |
+6,270,810 |
+9.7% |
+0.08 |
+0.22 |
|
Geode Capital |
+5,695,057 |
+3.9% |
+0.11 |
+0.18 |
|
Goldman Sachs |
+5,610,937 |
+10.7% |
+0.07 |
+0.18 |
Common-stock positions only. Options-based holdings (puts and calls) are excluded from the drift calculation. GOOGL Class A shares. Common Share Change and Pct Change come directly from 13F filings. Active Weight and Drift Score are framework-derived: Active Weight is the trade-driven residual after removing price movement, and Drift Score is the composite ranking measure defined in the methodology. The table is ranked by Drift Score, not by share change.
The accumulator side needs a careful read, and this is where the methodology earns its place. Three of the top names, SG Americas Securities, Arrowstreet Capital, and Value Aligned Research, are quantitative or market-making entities. Their scores reflect strategy mechanics, systematic rebalancing, hedging books, or a small base scaling up fast, rather than a fundamental view on Alphabet. Value Aligned's 389.8% jump looks dramatic, but it comes off a small base and is a different kind of event from Berkshire committing roughly $10 billion of new capital. The drift framework surfaces all of them because they moved sharply. Reading the table well means separating Berkshire's unusually clear active accumulation from other large-filer moves that may reflect index exposure, diversified platform activity, systematic strategies, or smaller-base effects, rather than assuming every high score is the same kind of signal.
This is exactly the universe-construction judgment the underlying data makes possible. Because FMP exposes every filer's full position detail, prior-quarter baseline, and security type in one place, the accumulator list can be read critically rather than taken at face value. The same decomposition that told us Berkshire's move was active rather than passive also lets us see that Value Aligned's move, while large in percentage terms, is not the same species of signal. A raw ranking of quarter-over-quarter change would have blurred those distinctions. Reading them apart is the difference between data and analysis.
Berkshire's Accumulation Met a Divided Field
Conviction is more interesting when it is contested, and Alphabet in Q1 2026 was contested. While Berkshire built, a cluster of large managers cut.
Top Active Reducers of Alphabet, Q1 2026
|
Filer |
Share Change |
Pct Change |
Active Weight |
Drift Score |
|
Wellington Management |
-9,665,827 |
-16.9% |
-0.33 |
-0.89 |
|
Capital International |
-9,715,527 |
-27.6% |
+0.13 |
-0.63 |
|
T. Rowe Price |
-3,456,238 |
-4.1% |
+0.07 |
-0.40 |
|
Susquehanna |
-4,223,000 |
-18.7% |
-0.16 |
-0.40 |
|
Deutsche Bank |
-2,413,836 |
-7.6% |
-0.19 |
-0.35 |
|
State Street |
-2,037,823 |
-0.9% |
+0.04 |
-0.33 |
|
Royal Bank of Canada |
-2,588,568 |
-6.8% |
+0.01 |
-0.32 |
|
Ameriprise |
-1,916,127 |
-5.5% |
-0.07 |
-0.30 |
Common-stock positions only. Options-based holdings (puts and calls) are excluded from the drift calculation. GOOGL Class A shares. This table shows active position reduction within the 13F Drift Framework. It is not a bearish signal, a forecast, or an investment conclusion on its own.
Wellington is the clearest active seller in the group: it shed close to 9.7 million shares, cut 16.9% of its position, and its active weight change of -0.33 confirms the reduction was driven by selling rather than by price. The rest of the cluster rewards a closer look. Capital International cut its share count by 27.6%, the largest percentage reduction in the group, yet its active weight change is slightly positive. Its drift score is still clearly negative because the composite blends three inputs: the sharp negative share-count change and negative percentage change outweigh the small positive active-weight component, so the overall score lands well below zero. It is a useful reminder that the drift score is a weighted composite, not a single field, and that a large share-count cut and an active-conviction reduction are not always the same thing. Deutsche Bank and a set of banks trimmed on both measures. Taken together, the reducers are the counterweight to Berkshire: as one investor committed capital, several long-established holders were stepping back during a quarter when Alphabet's long-term growth and search economics were being actively debated. The framework does not adjudicate who is right. It quantifies the split cleanly, which is the point.
What This Tells Us, and What It Does Not
The drift framework establishes what happened with unusual clarity: Berkshire made a high-conviction, actively-bought commitment to Alphabet during a quarter when the price fell and several established holders were reducing. That is a real and unusually clean signal.
What it does not establish is what happens next. This is a single-quarter reading. A manager who builds aggressively in one quarter may keep building, hold, or reverse, and 13F data arrives with a 45-day lag, so the positions described here are already several weeks old by the time they are public. The framework treats a single-quarter drift score as an attention signal, a reason to look closely, rather than a conviction signal on its own. The purpose of the case study is to show how the framework changes the read on a contested ownership move, not to forecast Alphabet's returns. The stronger read comes from watching whether Berkshire's commitment persists across the next two quarters, which future case studies in this series will track as the filings arrive. For now, the quarter's clearest fact stands on its own: when GOOGL's price fell and much of the field stepped back, Berkshire stepped in, and it stepped in on purpose.
For the full methodology and the code to reproduce this analysis on any name, see the framework page.
