Stock Trading Canary

United States · SEC Form 4 · Snapshot date: 2026-10-18 · Built: 2026-10-18 · 中文

← United States · Coverage record

US · SEC FORM 4

BERKSHIRE HATHAWAY INC

BRK.B · NYSE · CIK 0001067983 · Financial Services · Insurance—Diversified

INSIDER SIGNAL

50.3 / 100

1 buyers · 5 purchase transaction lines · $500.6K gross purchase

WHY THIS SIGNAL?

Buyer breadthLow
Purchase sizeModerate
RoleModerate
RecencyLow
ConvictionStrong
Score anatomy

Each bar shows the contribution to the current score; the weights and formula stay unchanged.

Cluster+7.0 / 35
Purchase size+14.6 / 25
Role+15.5 / 20
Recency+3.3 / 10
Conviction+10.0 / 10

What is holding the score back?

  • ⚠ Cluster breadth is moderate · 1 insider(s), not 4+
  • ⚠ Role uses the day's average · no purchase states a title on the role scale
  • ⚠ Purchase activity is becoming less recent

Purchase-size comments are relative to the model scale. Average daily volume is a separate market-context diagnostic.

US-v1.2 ranks qualifying equity purchases under the current 180-day rules. The score is a research priority, not a return forecast or probability. Backtests have not shown that a higher US score is followed by better returns.

Insider activity timeline

Owner lanes show the latest 180 days. Symbol shape identifies the transaction type; sales remain context only.

AprMayJunJulAugSepOct
BUFFETT WARREN EDirector,TenPercentOwner
○○○○○
Jain AjitVice Chairman
○○▼
O'Sullivan Michael J.See Remarks
●●
GUYMAN CHARLOTTEDirector
○
● Purchase▼ Sale○ Other

—

Purchase breadth & concentration

QUALIFYING BUYERS1
PURCHASE CONCENTRATION100%Largest buyer: O'Sullivan Michael J. · $500.6K
CLUSTER BUYING · 15D1 insiderPeak activity: 2026-05-06–2026-05-06

Roles in the peak window: See Remarks. Concentration uses priced qualifying P lines only and does not change the saved score.

SIGNAL HISTORY

50.3 / 100

Latest recorded score

↓ -0.2 ptsversus the previous recorded snapshot
  1. 50.8
  2. 50.7
  3. 50.6
  4. 50.5
  5. 50.3

Only scores saved when a full US scoring run completed are shown; gaps are not reconstructed.

Recent Form 4 activity

5Purchases
1Sales
16Other Form 4 lines
13SEC filings · 365 days
BUYING5 qualifying P line(s) · 180 days
SELLING1 sale line(s) · context only
OTHER9 exercise / withholding / award / gift / other lines
10b5-1 / PLANNEDNot assessed

P is an open-market or private purchase. S is a sale. M, F, A and G usually describe exercises, tax withholding, awards and gifts. These categories remain visually separate.

Market context

Market context provides additional background on recent price performance and risk. It does not affect the Insider Signal.

Price performance

1M
+1.7%
3M
+3.8%
6M
+7.4%
12M
+3.2%

Volatility & liquidity

Volatility
17.0%
Beta
—
Avg daily value
USD 2.2B

Valuation

Market cap
—
P/E
—

Fundamentals

Profit margin
18.0%
ROE
9.3%
Industry
Insurance—Diversified

Market data

Price data up to: 2026-10-11 · Price source: OpenBB/yfinance; volume from price cache (yfinance) · From SEC filings: Profit margin, ROE · Fiscal year ended: 2025-12-31 · Status: PASS

Short interest

Short interest is external context reported to FINRA by broker-dealers. It does not affect the Insider Signal.

Shares short
12,370,081
Previous report
12,529,378
Avg daily volume
5,322,205
Days to cover
2.3

FINRA settlement date: 2026-09-30 · Captured 2026-10-12 · FINRA equity short interest ↗. A share count, published about a week after each of two settlement dates a month; not a percentage of shares outstanding.

Historical equity purchases

Qualifying code P transactions in the local Form 4 history, including purchases outside the current signal window.

Transaction dateReporting ownerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-12O'Sullivan Michael J.Purchase (P)Class B Common Stock488USD 512.44USD 250,072SEC filing ↗
2026-05-06O'Sullivan Michael J.Purchase (P)Class B Common Stock536USD 467.44USD 250,545SEC filing ↗
2022-09-29Abel GregoryPurchase (P)Class A Common Stock1USD —USD —SEC filing ↗
2022-09-29Abel GregoryPurchase (P)Class A Common Stock3USD —USD —SEC filing ↗
2022-09-29Abel GregoryPurchase (P)Class A Common Stock23USD —USD —SEC filing ↗
2022-09-29Abel GregoryPurchase (P)Class A Common Stock38USD —USD —SEC filing ↗
2022-07-05OLSON RONALD LPurchase (P)Class B Common Stock2,410USD 274.35USD 661,183SEC filing ↗
2020-12-18OLSON RONALD LPurchase (P)Class B Common Stock4,000USD 222.33USD 889,320SEC filing ↗
2020-05-18WITMER MERYL BPurchase (P)Class B Common Stock1,000USD 173.30USD 173,300SEC filing ↗
2020-05-18WITMER MERYL BPurchase (P)Class A Common Stock3USD —USD —SEC filing ↗

Form 4 evidence

22 transaction lines in the latest 365-day window; 155 in local history.

DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-09-28Jain AjitSale (S)Class B Common Stock39,700USD 503.09USD 19,972,673SEC filing ↗
2026-09-03Jain AjitGift (G)Class B Common Stock10USD —USD —SEC filing ↗
2026-08-12O'Sullivan Michael J.Purchase (P)Class B Common Stock488USD 512.44USD 250,072SEC filing ↗
Show recent Form 4 evidence (17 grouped rows)
DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-09-28Jain AjitSale (S)Class B Common Stock39,700USD 503.09USD 19,972,673SEC filing ↗
2026-09-03Jain AjitGift (G)Class B Common Stock10USD —USD —SEC filing ↗
2026-08-12O'Sullivan Michael J.Purchase (P)Class B Common Stock488USD 512.44USD 250,072SEC filing ↗
2026-07-14BUFFETT WARREN EGift (G)Class B Common Stock10,000,000USD 0.00USD 0SEC filing ↗
2026-07-14BUFFETT WARREN EC (C)Class B Common Stock12,000,000USD 0.00USD 0SEC filing ↗
2026-07-01Jain AjitGift (G)Class B Common Stock3USD —USD —SEC filing ↗
2026-05-22BUFFETT WARREN EGift (G)Class B Common Stock160USD 0.00USD 0SEC filing ↗
2026-05-18BUFFETT WARREN EGift (G)Class B Common Stock18,646USD 0.00USD 0SEC filing ↗
2026-05-18BUFFETT WARREN EC (C)Class B Common Stock37,500USD 0.00USD 0SEC filing ↗
2026-05-14GUYMAN CHARLOTTEGift (G)Class B Common Stock574USD 0.00USD 0SEC filing ↗
2026-05-06O'Sullivan Michael J.Purchase (P)Class B Common Stock536USD 467.44USD 250,545SEC filing ↗
2026-03-27Jain AjitGift (G)Class B Common Stock22USD —USD —SEC filing ↗
2025-11-10BUFFETT WARREN EGift (G)Class B Common Stock1,900,000USD 0.00USD 0SEC filing ↗
2025-11-10BUFFETT WARREN EC (C)Class B Common Stock2,700,000USD 0.00USD 0SEC filing ↗
2025-11-03GUYMAN CHARLOTTEGift (G)Class B Common Stock410USD 0.00USD 0SEC filing ↗
2025-11-03GUYMAN CHARLOTTEC (C)Class B Common Stock1,500USD 0.00USD 0SEC filing ↗
2025-10-22Jain AjitGift (G)Class B Common Stock32USD —USD —SEC filing ↗

Multiple price lines in one filing are grouped and share-weighted. Price and value are blank when a grouped filing line lacks price evidence.

Snapshot & identity

Snapshot date2026-10-18
Ranking versionUS-v1.2
Data qualityPASS ELIGIBLE · —
TickerBRK.B
CIK0001067983
SectorFinancial Services
IndustryInsurance—Diversified Yahoo Finance
SEC SIC6331 Fire, Marine & Casualty Insurance
ExchangeNYSE

Data coverage

Local Form 4 history155 transaction lines from 2020-02-28 to 2026-09-28
26 P purchase lines · 15 S sale lines · 114 other lines
SEC company submissionsOpen SEC filings ↗

Local ledger as of 2026-10-18. Mapping status is an audit field and does not erase SEC filing evidence.