Buteon Research / 13F Timing Lab
The holdings date, the public filing and your entry are three different moments. Replay real disclosures. See what changing the timing changes.
Explore the record
Berkshire Hathaway · Q3 2025
Read the dates before the headline
45 days between the portfolio snapshot and the filing. Calendar days, not trading sessions.
We do not know the manager’s purchase date or price. Changing your entry moves only your replay; the exit stays fixed. Timeline steps are equally spaced, not a time scale.
Entry: Nov 17, 2025 at $285.02. Exit: Feb 13, 2026 at $305.72. 60 trading sessions between closes.
The exit stays Feb 13, 2026. Waiting shortens the holding period. “pp” means percentage points; this is a price comparison, not risk-adjusted alpha.
Scroll sideways to compare every column ↔
| Entry timing | Entry date | GOOGL | SPY | Difference |
|---|---|---|---|---|
| First session | Nov 17, 2025 | +7.26% | +2.42% | +4.85 pp |
| Wait 1 session | Nov 18, 2025 | +7.54% | +3.28% | +4.26 pp |
| Wait 5 sessions | Nov 24, 2025 | -4.04% | +1.95% | -5.98 pp |
| Date | GOOGL | SPY |
|---|---|---|
| Nov 17, 2025 | $285.02 | $665.67 |
| Nov 18, 2025 | $284.28 | $660.08 |
| Nov 19, 2025 | $292.81 | $662.63 |
| Nov 20, 2025 | $289.45 | $652.53 |
| Nov 21, 2025 | $299.66 | $659.03 |
| Nov 24, 2025 | $318.58 | $668.73 |
| Nov 25, 2025 | $323.44 | $675.02 |
| Nov 26, 2025 | $319.95 | $679.68 |
| Nov 28, 2025 | $320.18 | $683.39 |
| Dec 1, 2025 | $314.89 | $680.27 |
| Dec 2, 2025 | $315.81 | $681.53 |
| Dec 3, 2025 | $319.63 | $683.89 |
| Dec 4, 2025 | $317.62 | $684.39 |
| Dec 5, 2025 | $321.27 | $685.69 |
| Dec 8, 2025 | $313.72 | $683.63 |
| Dec 9, 2025 | $317.08 | $683.04 |
| Dec 10, 2025 | $320.21 | $687.57 |
| Dec 11, 2025 | $312.43 | $689.17 |
| Dec 12, 2025 | $309.29 | $681.76 |
| Dec 15, 2025 | $308.22 | $680.73 |
| Dec 16, 2025 | $306.57 | $678.87 |
| Dec 17, 2025 | $296.72 | $671.40 |
| Dec 18, 2025 | $302.46 | $676.47 |
| Dec 19, 2025 | $307.16 | $680.59 |
| Dec 22, 2025 | $309.78 | $684.83 |
| Dec 23, 2025 | $314.35 | $687.96 |
| Dec 24, 2025 | $314.09 | $690.38 |
| Dec 26, 2025 | $313.51 | $690.31 |
| Dec 29, 2025 | $313.56 | $687.85 |
| Dec 30, 2025 | $313.85 | $687.01 |
| Dec 31, 2025 | $313.00 | $681.92 |
| Jan 2, 2026 | $315.15 | $683.17 |
| Jan 5, 2026 | $316.54 | $687.72 |
| Jan 6, 2026 | $314.34 | $691.81 |
| Jan 7, 2026 | $321.98 | $689.58 |
| Jan 8, 2026 | $325.44 | $689.51 |
| Jan 9, 2026 | $328.57 | $694.07 |
| Jan 12, 2026 | $331.86 | $695.16 |
| Jan 13, 2026 | $335.97 | $693.77 |
| Jan 14, 2026 | $335.84 | $690.36 |
| Jan 15, 2026 | $332.78 | $692.24 |
| Jan 16, 2026 | $330.00 | $691.66 |
| Jan 20, 2026 | $322.00 | $677.58 |
| Jan 21, 2026 | $328.38 | $685.40 |
| Jan 22, 2026 | $330.54 | $688.98 |
| Jan 23, 2026 | $327.93 | $689.23 |
| Jan 26, 2026 | $333.26 | $692.73 |
| Jan 27, 2026 | $334.55 | $695.49 |
| Jan 28, 2026 | $336.01 | $695.42 |
| Jan 29, 2026 | $338.25 | $694.04 |
| Jan 30, 2026 | $338.00 | $691.97 |
| Feb 2, 2026 | $343.69 | $695.41 |
| Feb 3, 2026 | $339.71 | $689.53 |
| Feb 4, 2026 | $333.04 | $686.19 |
| Feb 5, 2026 | $331.25 | $677.62 |
| Feb 6, 2026 | $322.86 | $690.62 |
| Feb 9, 2026 | $324.32 | $693.95 |
| Feb 10, 2026 | $318.58 | $692.12 |
| Feb 11, 2026 | $310.96 | $691.96 |
| Feb 12, 2026 | $309.00 | $681.27 |
| Feb 13, 2026 | $305.72 | $681.75 |
These selected historical cases are not a strategy test. Price movements can reflect earnings, market news and other events. These comparisons do not establish that the filing caused the move or that copying a manager works.
The six-case comparison
Read across a case to compare entry dates. Read down to see how different the outcomes were.
“First session” means the next trading session’s closing price after the filing. Each case keeps its own exit date fixed, 60 sessions after that base entry. Waiting 1 or 5 sessions means holding for 59 or 55 sessions. These cases took place in different years.
60-session exit window. Showing stock price changes. A minus sign means the stock lost value; SPY below each result shows the market over the same entry and exit dates.
What waiting 5 sessions changed The stock price change was 11.30 percentage points lower than entering at the first session’s close.
What waiting 5 sessions changed The stock price change was 1.17 percentage points lower than entering at the first session’s close.
What waiting 5 sessions changed The stock price change was 4.56 percentage points higher than entering at the first session’s close.
What waiting 5 sessions changed The stock price change was 3.01 percentage points lower than entering at the first session’s close.
What waiting 5 sessions changed The stock price change was 7.84 percentage points higher than entering at the first session’s close. The delayed entry still lost money.
What waiting 5 sessions changed The stock price change was 0.14 percentage points higher than entering at the first session’s close. The delayed entry still lost money.
Six examples selected with hindsight, not a test of whether waiting usually works. These are hypothetical follower price changes, not the managers’ returns. Dividends, trading costs, taxes and slippage are excluded. Read the calculation method ↗
After the Filing / Quarterly reports
Two complete Q3 2025 new-common-stock cohorts. The managers and quarter were selected with hindsight; positions within each report follow the same published rule.
The Alphabet entry—and what a five-session wait changed.
1 new common-stock position · 41 disclosed security/option pairs reviewed · 20 & 60 sessions complete
Molina, SLM, and why the AI put headlines need a different reading.
2 new common-stock positions · 8 disclosed security/option pairs reviewed · 20 & 60 sessions complete
The reviewed collection
Six deliberately selected examples: gains, losses and stocks that trailed the market. The second batch adds TSMC, Alibaba and Rivian to show contrasting outcomes, not to estimate a success rate. Every return shown below uses the first-session entry and the same 60-session rule. “pp” means percentage points. This is not a representative sample.
Berkshire’s November 2025 filing reported Alphabet Class A shares that were absent from its June information table. The filing arrived after the Friday close; the replay starts at Monday’s close.
Berkshire’s August 2025 filing reported UnitedHealth common shares. The Thursday after-close disclosure and Friday closing-price entry let you examine what waiting changed over a fixed observation window.
Pershing Square’s May 2025 13F reported Uber shares, but the stake had already been announced in February. This case shows why a newly reported 13F position need not be a fresh market revelation.
Berkshire’s November 2022 filing reported TSMC’s U.S.-listed depositary shares. The first-session replay looks different at 20 and 60 trading sessions: an early loss becomes a later gain.
Michael Burry’s Scion reported 50,000 Alibaba depositary shares in February 2023. From the next session’s close, BABA lost value and trailed SPY at both observation windows.
Soros Fund Management reported nearly 19.84 million Rivian shares after the EV maker’s 2021 IPO. The following replay window includes a steep loss, even though the filing carried a famous name.
How to read the numbers
The base entry is the next trading session’s close after the filing date, whether the filing arrived during trading or after the close. Scion’s Alibaba filing arrived during market hours; the other selected filings arrived after the close. It is a reproducible daily-price convention, not the earliest executable trade. Overnight and first-session moves are already in that entry price.
Choose an exit 20 or 60 trading sessions after the base entry. Waiting one or five sessions moves the entry only. All scenarios exit on the same date; delayed entries therefore have shorter holding periods. Sessions follow the observed SPY trading dates, including holiday gaps.
Price change = (exit close ÷ entry close − 1) × 100. SPY uses the same dates. The difference is measured in percentage points, not risk-adjusted alpha. The chart rebases both series to 100 at the selected entry. Prices are USD closes from Yahoo Finance; the reviewed windows contain no recorded stock splits.
Dividends, trading costs, taxes and slippage are excluded. The snapshot-to-filing comparison is not the manager’s return. A weekend quarter-end uses the last trading close on or before that date. For an intraday filing, the filing-day close includes post-disclosure trading. Options, short positions and a manager’s actual trade dates are not reconstructed. These six selected cases cannot establish causation, predictive power or a profitable strategy.
Download all six cases’ prices (CSV) ↓ · Read the research · Report a correction
Reviewed snapshot · Oct 24, 2026 · Version 2026-10-24.1. Source retrieval and calculation checks are part of this release. No live prices or automatic refresh are implied.
Financial interest: the publisher/researcher has disclosed a GOOGL holding in Buteon’s Alphabet research. This collection includes GOOGL. Educational research, not an investment recommendation.
Common questions
You can research disclosed positions, but the filing is an incomplete, delayed snapshot. It does not supply the manager’s trade dates, cost basis, short positions or current portfolio. This lab measures selected stock-price windows after disclosure, not fund performance.
No. It means a security appears in the reviewed current table and not the reviewed prior-quarter public records. Trades can predate quarter-end, and confidentiality, amendments or other earlier disclosures can change what “new” means. Each case records its comparison sources.
Most selected filings arrived after that close, so using it would grant a follower a price from before disclosure. Scion’s Alibaba filing arrived during market hours. We use the next session’s close for every case to keep the convention consistent; it is not the earliest opportunity to trade.
No. Earnings, economic news and other disclosures may overlap the window. Even a positive difference versus SPY is descriptive; it is not a causal estimate or evidence that the strategy will repeat.