By Kresmion Research, October 20, 2026
Berkshire Hathaway bought 7,502,076 Lennar shares for $595.3 million at an average of $79.35, and Lennar closed at $75.87 on October 19, 4.4 percent below it. The purchases were 43 open-market trades on 11 of the 12 sessions from September 17 to October 2, none under a 10b5-1 plan. No Berkshire Form 4 for Lennar covers a trade after October 2, though trades in the last two to three sessions could still be unfiled. The buying came as the 30-year mortgage rate rose from 6.95 percent to 7.28 percent, and the rate has since printed 7.40 percent twice. This note describes filings and prices only. It is not advice, and the data does not show why Berkshire bought or why it paused.
Key takeaways
| What | Number |
|---|---|
| Berkshire Form 4 purchases in Lennar, September 17 to October 2 | 7,502,076 shares (Class A and B), $595,278,962, 43 trades on 11 trade dates, all code P, none under a 10b5-1 plan (Kresmion insider_trades, 4 filings) |
| Average price against the latest close | $79.35 average. Lennar closed at 75.87 on October 19. The paper result on the Form 4 lot is about minus $26.1 million, minus 4.4 percent (approximate, mixes Class A and B lots) |
| Share of Lennar volume | About 10.0 percent of reported daily volume across the 11 buying days (7,502,076 of 74,761,900 volume on those days, numerator includes Class B). The daily range was 0.1 to 18.9 percent |
| Stake | 28,438,045 Class A shares after October 2 (Investing.com, an AI-assisted page that misstates Berkshire as a director), 13.68 percent of the 207,876,222 Class A shares in Lennar's 10-Q. The 13F count was 7,050,950 on September 30, 2025, 3.39 percent |
| Rates while buying | 30-year mortgage rate 6.95 (September 17) to 7.28 (October 1), then 7.40 on October 8 and October 15, the highest since November 16, 2023. 10-year Treasury 4.94 to 5.28 |
| Trades after October 2 | No Form 4 in Kresmion insider_trades covers one. The table's latest trade date is October 19, and trades in the last two to three sessions could still be unfiled |
What the data shows
Four Form 4 filings (accessions 0001193125-26-397059, -403089, -409451 and -414744) cover the buying. Every row is transaction code P, the insider role is "10% Owner" and the 10b5-1 flag is false on all 43 rows. Trade-level weighted prices run from 74.80 (a Class B lot) to 81.96. The biggest day was October 2, with $135.7 million (1,708,095 shares), followed by September 18 with $105.6 million (1,381,397 shares). The smallest were September 28 at $0.43 million (5,200 shares) and September 29 at $1.01 million (12,289 shares).
The first filing, which we fetched from the SEC (Form 4), names Berkshire Hathaway Inc and Warren E. Buffett as reporting owners, marks Berkshire as a ten percent owner and not a director, and lists the holders as insurance and related subsidiaries, including National Indemnity (12,366,349 Class A), BHG Life (3,625,000), AZGUARD (3,098,000) and Medical Protective (2,216,760). After the September 17 to 21 purchases it shows 23,719,109 Class A shares. The first September 17 row brings the total to 21,318,186 after 267,585 shares, which implies 21,050,601 shares before the buying.
The pace has picked up. Berkshire's 13F Class A count in Kresmion institutional_holdings was 7,050,950 on September 30, 2025 and December 31, 2025, then 10,099,642 on March 31, 2026 (up 3,048,692) and 13,111,741 on June 30 (up 3,012,099). From the 13F to the pre-September 17 Form 4 count, about 7,938,860 Class A shares were added between July 1 and September 16 and not individually reported (derived by subtraction). The Form 4 sessions added about 7,387,244 Class A shares (derived: the database total less 114,832 Class B shares). Investing.com reports 28,438,045 Class A and 568,028 Class B shares after the October 1 and 2 purchases of $192,634,432 (our database total for those two days is about $8,000 lower). That is about four times the 2025 count. The page calls Berkshire a director, which the Form 4 contradicts. Our own reconciliation gives 28,437,845, a gap of 200 shares, and we did not fetch the last three filings directly.
The denominator for the stake is Lennar's 10-Q: 207,876,222 Class A and 30,024,017 Class B shares outstanding on August 31, 2026. That date is earlier than the holdings count, so the 13.68 percent is approximate.
The price path: Lennar closed at 78.36 on September 16, 79.70 on September 17 and 78.08 on September 21. On September 22, the first session after the first Form 4 was signed (September 21), it closed at 83.06, up 6.4 percent, but D.R. Horton rose 3.5 percent and PulteGroup 2.8 percent that day, so about half of the move was shared with the sector. Lennar fell 4.1 percent on September 18, a day Berkshire bought $105.6 million. It was 79.81 on October 2, fell 6.7 percent to 74.44 on October 5 (D.R. Horton fell 1.3 percent, PulteGroup 1.5 percent), touched 73.53 on October 14 and closed at 77.08 on October 16 and 75.87 on October 19. The data does not show what drove those moves. Since September 16, Lennar is down 3.2 percent, D.R. Horton 2.2 percent and PulteGroup 5.7 percent. Since January 2, Lennar is down 27.2 percent, against 7.1 percent for D.R. Horton and 6.9 percent for PulteGroup.
The mechanism
The holders include insurance subsidiaries, which suggests insurance float buying a stock that is sensitive to interest rates. That is an inference from the holder names. A homebuilder's margins depend on what buyers can afford to borrow. The 30-year mortgage rate (Freddie Mac, via FRED) was 6.43 on July 2, 6.95 on September 17, 7.03 on September 24 and 7.28 on October 1, then 7.40 on October 8 and 15. The 10-year Treasury yield went from 4.94 on September 17 to 5.28 on October 2 and peaked at 5.31 on October 5, its highest since May 14, 2002. NAHB's October builder index came in at 29 against a forecast of 31, from 32 the month before (Babypips). The pattern fits a buyer paying for a discount that higher rates created. That is an inference from timing. The filings carry no statement of intent.
Berkshire was a large share of Lennar's trading. Across the 11 days Berkshire bought, its shares were about a tenth of reported volume (7,502,076 of 74,761,900 on those days), reaching 18.9 percent on October 2. Over the buying window, September 16 to October 2, Lennar rose 1.9 percent while D.R. Horton fell 2.4 percent and PulteGroup fell 1.5 percent. The weakness came after the buying stopped: from October 2 to October 19 Lennar fell 4.9 percent, D.R. Horton rose 0.2 percent and PulteGroup fell 4.2 percent. The data does not show why.
Two second-order points follow. First, the 6.4 percent jump on September 22 had been given back by October 5, but about half of it was shared with D.R. Horton and PulteGroup that day, and Lennar's other large daily moves were minus 4.1 percent on September 18 and minus 6.7 percent on October 5. The data cannot say whether the disclosure or the buying moved the price. Second, Berkshire is over 10 percent and so must report any trade within two business days. A Form 4 for a trade after October 2 would be observable once filed. The pause began while mortgage rates were making new highs and before the 10-year peaked on October 5. The reason for it is not in any data we hold.
Other explanations
A price ceiling. Berkshire may buy only when Lennar trades under a set level. Purchase prices sat between 74.80 and 81.96, which fits a ceiling. Berkshire bought nothing on September 22 (close 83.06) and little on September 28 and 29 (closes 82.03 and 83.01), which fits a ceiling near 82. But buying stopped while Lennar traded from 73.53 to 77.69 between October 5 and October 16, which a pure price-limit buyer would not do. A size target may have been reached. The size of any target is unknown.
Strategic interest. Crossing 10 percent and continuing to 13.68 percent could be a step toward a bigger holding or a deal. We have no evidence for that. The Form 4 shows no director seat and we did not check any 13D language.
A mechanical pause. An internal blackout, antitrust filing timing or trading-window rules around Lennar's calendar could explain the stop without any view on housing. None of that is visible in our data.
Earnings timing. Lennar announced fiscal third-quarter results after the close on September 16 (Kresmion earnings_calendar), and Investing.com reports a miss. Berkshire's first reported purchases came the next session, and the highest-volume days at the start of the window are post-earnings days, so the volume share and the early price moves are not a clean read on Berkshire alone.
Reporting lag. A Form 4 is due within two business days, so a trade on October 16 to 19 might not be in the table yet. That covers only the last two to three sessions, and not October 5 to 14.
The base rate
Size: $595.3 million ranks 2 of 1,141 insider-ticker totals of non-plan open-market purchases in Kresmion insider_trades. Only Cascade Investment's $1.38 billion in Republic Services (August 10 to September 11) is larger, and only 7 totals exceed $100 million. This is a short-window rank. Purchase rows in the table jump in August 2026 (1,090 purchase rows in August, against 6 to 17 a month from April to July).
Rates: 9 of 524 weekly readings of the 30-year mortgage rate since October 1, 2016 are at or above 7.40. The last one before this October was November 16, 2023, and the series high since 2022 is 7.79 on October 26, 2023. The 10-year at 5.31 was the highest since 2002 in a series that starts in 1962.
Stake: 13.68 percent of Class A, from 3.39 percent at September 30, 2025.
We did not compute a forward-return base rate for large holder purchases, because the table window is too short. Magnitude unknown. The Berkshire holdings series (13F, Form 4 and the Investing.com count) all come from Berkshire's own filings, so they count as one source. Mortgage rates and the 10-year are linked, so they count as one rates fact. The lead is a disclosed fact.
The evidence against
Lennar's weakness came after Berkshire stopped buying. From September 16 to October 2 it rose 1.9 percent against falls of 2.4 percent for D.R. Horton and 1.5 percent for PulteGroup. From October 2 to October 19 it fell 4.9 percent while D.R. Horton rose 0.2 percent and PulteGroup fell 4.2 percent. Over the whole period since September 16 Lennar is down 3.2 percent, between D.R. Horton (2.2) and PulteGroup (5.7). The 6.4 percent jump on September 22 was fully reversed by October 5. The Form 4 lot is underwater only because of the drop after October 2. The post-October 2 holding count also rests on a page that misstates Berkshire as a director, though our reconciliation sits within 200 shares of it.
What would change the read
1. A new Berkshire Form 4 for Lennar on SEC EDGAR, due within two business days of a trade. Purchases below 79.35 would mean the pause was not a stop. Any sale (code S) would reverse the read. 2. Berkshire's Q3 2026 13F, due by Monday November 16 (the 45th day, November 14, is a Saturday). Class A holdings consistent with the Form 4 path would confirm the count. A gap would point to holdings outside the reported entities. 3. The Freddie Mac weekly rate on Thursday October 22. A print below 7.03, the September 24 level during the buying, would remove the rate-pressure part of the story. Housing starts and building permits are also out today, October 20. 4. A Lennar close above 79.35 would put the Form 4 lot back above water. The last Berkshire purchase in our data was on October 2, at prices up to 81.96. 5. Lennar's fourth-quarter report is scheduled for December 14 (Kresmion earnings_calendar).
Frequently asked questions
How much has Berkshire bought of Lennar?
Berkshire bought 7,502,076 Class A and Class B shares for $595,278,962 across 43 Form 4 trades on 11 dates from September 17 to October 2, 2026. The average was $79.35 a share. Investing.com reports 28,438,045 Class A shares held afterward, 13.68 percent of the 207,876,222 Class A shares in Lennar's 10-Q.
Is Berkshire ahead or behind on the position?
On the Form 4 lot, behind. Lennar closed at 75.87 on October 19, about 4.4 percent below the 79.35 average, roughly minus $26.1 million. The figure is approximate because it mixes Class A and B lots, and it ignores Berkshire's earlier shares.
Has Berkshire stopped buying?
No Form 4 for a trade after October 2 is in Kresmion insider_trades, whose latest trade date is October 19. Filings are due within two business days, so trades on the last two to three sessions could be missing. The reason for any pause is not in the data.
How high are mortgage rates?
The Freddie Mac 30-year rate was 7.40 percent on October 8 and October 15, the highest since November 16, 2023. It was 6.95 on September 17. The next reading is Thursday October 22.
When is the next data point?
The Freddie Mac rate and jobless claims are due Thursday October 22. Berkshire's Q3 13F is due by Monday November 16.
Sources
SEC Form 4, Berkshire Hathaway Inc and Warren E. Buffett, Lennar, period September 17, 2026: purchases through September 21, ten percent owner and not a director, no 10b5-1, Class A holdings and subsidiary breakdown.
Lennar Form 10-Q for the quarter ended August 31, 2026: 207,876,222 Class A and 30,024,017 Class B shares outstanding.
Investing.com, Berkshire Hathaway increases Lennar stake with $192.6m stock purchase, October 5, 2026: post-October 2 holdings of 28,438,045 Class A and 568,028 Class B shares. The page misdescribes Berkshire as a director.
Babypips, Financial and Forex Market Recap, October 19, 2026: NAHB index 29 against a forecast of 31 and 32 prior.
Gotrade, Weekly economic outlook, week of October 19, 2026: housing starts and permits on October 20, jobless claims on October 22.
Kresmion insider_trades (database table): Berkshire Lennar purchases by date and filing, volume share, and the rank among non-plan open-market purchase totals. Latest trade date October 19.
Kresmion institutional_holdings (database table): Berkshire 13F Lennar Class A and B counts, September 30, 2025 to June 30, 2026.
Kresmion company_price_snapshots (database table): LEN, DHI and PHM daily closes, January 2 to October 19, 2026.
Kresmion fred_series_history (database table): MORTGAGE30US through October 15 and DGS10 through October 16.