Will Ajit Jain file Form 4 disclosing additional discretionary BRK share sales in H1 2026?

The 5-6 month non-selling window from Sep 2025 through Mar 2026 is the most significant new data point. Jain had the same price opportunity in Q4 2025 (~$465-$501 range) that he used in Aug-Sep 2025 and chose not to sell. This is strong Bayesian evidence that the prior sales were one-time rebalancing tied to stepping down as insurance chief, not the start of a distribution pattern. With ~4 months remaining in the H1 2026 window and no new role-change catalyst, the base rate for selling in any 4-month window is low. The prior 0.27 implicitly priced in Q4 2025 uncertainty that is now resolved NO. Key residual risk: Jain is 72 and may continue gradual diversification on an opportunistic basis, but the pause suggests he has completed the planned reduction.

Updating from 0.27 to reflect the FY2025 non-selling confirmation. The prior estimate was set when Q4 2025 was unobserved — now we have a full quarter of non-selling data plus the FY2025 10-K confirmation. Bayesian update: P(pattern|no Q4 sales) is substantially lower than P(pattern|unknown Q4). The benign interpretation — that the Aug-Sep 2025 sales were tied to Jain transitioning from active insurance chief to advisory Vice Chairman, a natural one-time rebalancing — gains credibility with each passing month of non-selling. However, I weight this slightly higher than my co-models because discretionary sales at ATH without 10b5-1 plan protection still suggests tactical timing ability that Jain could deploy again in spring/summer 2026. The 4-month window still leaves meaningful exposure.

The GOVERNANCE_ALIGNMENT signal upgraded to IMPROVING in the post-earnings lens update precisely because of the absence of new selling in FY2025. This is a cross-lens signal reinforcing the directional update. The Black Swan Beacon's original 15-30% tail probability for 'Jain sells additional shares in 2026' was conditioned on uncertainty about whether the Aug-Sep 2025 sales were a one-off. That uncertainty has substantially resolved. For H1 2026 resolution: Jan-Feb 2026 have passed without sales (confirmed by 10-K filing date), leaving approximately March-June 2026. Any new sale would now be more anomalous — it would follow a 7-month gap after the prior sales, making it even harder to interpret as pattern continuation vs. opportunistic rebalancing. Net: lower absolute probability, but the remaining window still has four months of meaningful exposure.

Updating from the prior 0.27 estimate. The key new information is: (1) No Q4 2025 sales confirmed by FY2025 10-K; (2) Jain remains in his Vice Chairman role with no announced changes; (3) BRK.B underperformed S&P by ~7pp in 2025, meaning the stock is somewhat cheaper than the ATH levels at which he sold in Aug-Sep 2025. If Jain was a price-sensitive tactical seller, lower prices argue against further near-term selling. The 4-month remaining window (March-June 2026) is meaningful, and senior executives at large holding companies do engage in periodic diversification, but the Q4 2025 non-event is strong evidence against active distribution. I weight slightly higher than peers to account for the possibility that Jain uses Q2 2026 (traditionally quieter insider trading window) for further rebalancing as he transitions further from operational responsibilities.

The prior 0.27 estimate was calibrated with the Aug-Sep 2025 sales as recent events and Q4 2025 as an open unknown. Now the Q4 unknown is resolved: no sales. The structural factors favoring NO remain: Berkshire culture under Abel emphasizes alignment, Jain retains board seat and is still connected to the company, no 10b5-1 plan suggests true discretionary decisions that can be paused. The structural factor that has increased: time elapsed since sales. Each month of non-selling reduces the conditional probability of continuation. Four months remain in the resolution window. Even if we assign a flat monthly probability of ~1% for any random month (consistent with the 0.17 annual rate), 4 months gives roughly 4% — but the actual distribution is not flat, and there's no known catalyst for H1 2026.

I take the most cautious view among the ensemble. While the 5-6 month non-selling window is clearly a positive update, I note: (1) Jain sold 10.5% of estimated holdings — a meaningful but not exhaustive position reduction; (2) He has no 10b5-1 plan, meaning future sales require active decision but are unconstrained by plan mechanics; (3) At age 72 and with reduced operational responsibilities, estate planning and diversification are ongoing considerations that could trigger selling in any quarter; (4) The question covers H1 2026, a 6-month window from inception, and we are roughly at the midpoint. The remaining 4 months is a substantial portion of the resolution window. I give the 0.20 floor rather than going lower because the absence of a clear 'never selling again' signal (like a Form 4 showing purchases, or entering a 10b5-1 plan) means the question remains genuinely open.

The FY2025 10-K update provides clean confirmation: no Jain sales in Q4 2025. Combined with the Sep 2025 endpoint, Jain has made a demonstrated choice not to sell for 5-6 consecutive months while remaining an active board member and Vice Chairman. This is not passive inaction — it is active discretionary non-selling. Given the prior 10-K analysis identified GOVERNANCE_ALIGNMENT as MIXED and the post-earnings update moved it to IMPROVING specifically citing no new selling, the directional signal is clear. The remaining analytical question is the base rate: what is the probability of any senior Berkshire executive selling shares in any given 4-month period? Historical precedent (Buffett, Munger until death, other directors) suggests this is rare. The Aug-Sep 2025 sales were anomalous by Berkshire standards; a return to non-selling appears to be the reversion-to-mean.

I assign the lowest probability in the ensemble. The Black Swan Beacon's original 15-30% for 'Jain sells additional shares in 2026' was calibrated when the Aug-Sep 2025 sales were fresh and the question was whether a pattern was forming. We now have 5-6 months of evidence that it was not a pattern. The lower bound of the Black Swan estimate (15%) was conditioned on this being a real escalation risk; the current data suggests we are tracking toward the lower end or below that estimate. Additionally: BRK.B underperformance in 2025 means lower absolute dollar incentive for selling at current prices vs. the ATH levels Jain chose to sell at. There is no positive signal that would increase the probability from here — the data is uniformly pointing toward non-continuation.

Balanced view: the update is clearly negative for the YES outcome, but four months remain and the question is not closed. Jain's stated rationale for the Aug-Sep 2025 sales has never been disclosed (no 10b5-1 plan means no plan document explaining the intent). This means we are reading the non-selling behavior without a stated framework. Two interpretations remain plausible: (A) one-time rebalancing at role transition, now complete — implies 10-15% probability for remaining 4 months; (B) annual diversification cadence (e.g., plans to sell once per year in H2 when less insider information is active) — implies only H2 2026 is at risk, making H1 2026 resolution less likely but not zero. Both interpretations point to 14-18% range. Settling at 0.17 as the central estimate.