Who made the largest insider stock purchases in the last three months?
Published
Answer · as of
The 10 largest open-market insider buyers of US-listed common stocks on Form 4 in the 63 sessions to Oct 23, 2026 spent $2.83B. Cascade Investment, reporting jointly with Bill Gates, bought $1.38B of Republic Services at an average of $220.69 a share, more than the next four buyers combined.
At the Oct 23 close, 5 of the 10 stocks were above the buyer’s average price, led by Suja Life (+16.4%) and Republic Services (+9.0%); Group 1 Automotive was 5.8% below.
Cascade accounts for almost half the total
Cascade Investment bought $1,380.3M of Republic Services from Aug 10 through Sep 11, 2026: 6,254,462 shares at a weighted average of $220.69. Its 12 Form 4s report more spending than the next four buyer groups combined. Cascade and Bill Gates report jointly as 10% owners.
The first filing and last filing show the holding rising from 110,803,982 to 117,058,444 shares. The footnotes give price ranges for groups of trades. Weighting each reported price by the shares bought gives the overall average. None of the filings flags a Rule 10b5-1 transaction.
RSG closed at $240.45 on Oct 23, 2026, 9.0% above Cascade’s average. Between the buying period and that close, it also traded below the average, as the daily closes show.
Berkshire and Conifer added to large holdings
Berkshire Hathaway bought $586.4M of Lennar Class A stock from Sep 17 through Oct 2, 2026: 7,387,444 shares at an average of $79.38. Its final filing reports 28,438,045 Class A shares and 568,028 Class B shares held through insurance subsidiaries. Berkshire spent another $8.8M on Class B shares, outside the Class A total. All four filings leave the plan flag unselected.
Conifer Management bought $187.3M of Group 1 Automotive from Sep 1 through Sep 30, 2026: 720,030 shares at $260.08 on average. The 10% owner’s last Form 4 reports 1,912,290 shares through investment vehicles it manages. Its six filings do not flag Rule 10b5-1 transactions.
At the Oct 23, 2026 close, LEN’s $84.92 was 7.0% above Berkshire’s average. GPI’s $244.97 was 5.8% below Conifer’s. GPI fell 27.4% over the 63 sessions, and Conifer’s filing averages fell from $275 in its Sep 3 filing to $242 in its Sep 30 filing as it kept buying.
Nippon bought $281.6 million under an earlier plan
Nippon Life bought $281.6M of Corebridge Financial from Sep 9 through Oct 20, 2026: 8,213,957 shares at an average of $34.29. Its 29 purchase filings end with 130,203,484 shares, including shares held by a wholly owned asset-management subsidiary. Nippon Life reports as a 10% owner. A 30th filing, accepted at 4:30 p.m. ET on Oct 23, 2026, after the cutoff, reports another 217,182 shares bought on Oct 21.
The purchase footnotes identify a Rule 10b5-1 plan adopted Aug 7, 2026. That plan predates every purchase in the sequence. The reported transactions record executions under that earlier plan.
Blackstone’s group had already sold $491.1M of Corebridge on Aug 10, 2026: 14,500,000 shares at $33.87. Its Form 4 reports 47,462,123 shares remaining through Argon Holdco and its ownership chain. It does not identify Nippon Life as the counterparty. CRBG closed at $34.13 on Oct 23, 2026, 0.5% below Nippon Life’s purchase average.
Baker Bros. bought $157.0 million in two days
Baker Bros.’ reporting group bought 1,941,755 Kodiak shares for $157.0M on Sep 28 and Sep 29, 2026, averaging $80.85. The three Form 4s filed Sep 30 report ending fund holdings totaling 21,860,941 shares. The final filing says space limitations required three forms.
Felix Baker serves as a Kodiak director. The filing explains that the other reporting persons are directors by deputization through that board representation. The adviser controls investment and voting decisions; the fund entities own the shares directly. None of the forms flags a Rule 10b5-1 transaction.
KOD closed at $87.63 on Oct 23, 2026, 8.4% above the purchase average. Its 109.1% closing-price increase over 63 sessions includes trading before the purchases.
Five more buyers spent between $20.1 million and $97.2 million
Ryan Cohen bought $97.2M of GameStop in five filings covering Sep 10 through Oct 13, 2026: 4,144,810 shares at $23.45 on average. His last filing reports 42,492,652 shares afterward. Tor Olav Trøim bought $57.1M of Borr Drilling from Aug 13 through Oct 15, 2026: 12,850,000 shares at $4.44 on average. His final filing reports 40,117,808 shares through Drew Holdings and explains its trust ownership.
Anthony Tan’s Grab filing reports 10,350,000 Class A shares bought on Sep 21, 2026, for $29.9M at $2.89, leaving 10,778,498 Class A shares. The Paine Schwartz group bought $29.0M of Suja from Aug 10 through Sep 8, 2026, at $8.45 on average. Its last filing reports 11,921,253 Class A shares across affiliated funds and aggregators.
Ernest Rady bought $20.1M of American Assets Trust from Aug 5 through Sep 14, 2026, at $22.57 on average. His ownership footnotes separate trusts, controlled entities and other holdings. None of these buyers’ purchase filings flags a Rule 10b5-1 transaction.
Three entries fall outside the market-purchase ranking
Catalyst4, a 10% owner, reported buying 4,400,000 MapLight shares for $50,072,000 on Aug 14, 2026, at $11.38 each. The Aug 13, 2026 8-K describes a private placement agreed that day at the same $11.38 per common share. The 8-K does not name the purchasers, but the matching price and date point to the placement rather than the open market, so the purchase is left out despite its code P classification.
Bluerock Private Real Estate Fund is a registered closed-end fund, as its registration statement confirms. Ramin Kamfar bought through controlled entities. The fund classification puts those purchases outside the operating-company common-stock ranking.
Bruno Mauad bought $22.7M of Aura Minerals common stock in the window, enough to rank tenth, but sold $119.3M of it: 1,381,952 shares. Both the purchases and the sales are held through Kapitalo Investimentos, as his Aug 28 Form 4 shows. A net seller of $96.6M is left out of a ranking of buyers. None of the ten buyers in the table sold more than it bought in the window.
Reading the purchase averages
Five of the ten stocks closed above the buyer’s average on Oct 23, 2026; Suja led at 16.4%, while Group 1 Automotive was furthest below at 5.8%. These comparisons cover purchases made on different dates, not returns on the buyers’ entire holdings. The filings give no stated reason for these purchases, and neither the purchases nor the closing-price comparisons forecast what happens next.
Ask it yourself
Using Monk.trade, which US-listed common stocks had the largest open-market insider purchases on SEC Form 4 over the last 63 sessions? Check the largest totals against their filings and leave out private placements, closed-end funds, and insiders who sold more of the stock than they bought. Who bought, and how do the latest closes compare with what they paid?
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The MonkQL Monk.trade ran
from universe all on daily include type == "common" where insiders(code = "p", window = 63).net > 0 show close, insiders(code = "p", window = 63).net as bought, insiders(code = "p", window = 63).count as form_4s, insiders(code = "s", window = 63).net as sold, 100 * (close / close[63] - 1) as chg_63 sort bought desc take 20
Run 01a175fb-0a70-70b1-bd49-dde87875f38d
| Buyer | Stock | Bought | Avg price | vs avg |
|---|---|---|---|---|
| Cascade (Bill Gates) | RSG | $1,380.3M | $220.69 | +9.0% |
| Berkshire Hathaway | LEN | $586.4M | $79.38 | +7.0% |
| Nippon Life | CRBG | $281.6M | $34.29 | −0.5% |
| Conifer Management | GPI | $187.3M | $260.08 | −5.8% |
| Baker Bros. | KOD | $157.0M | $80.85 | +8.4% |
| Ryan Cohen, CEO | GME | $97.2M | $23.45 | +5.8% |
| Tor Olav Trøim | BORR | $57.1M | $4.44 | −1.0% |
| Anthony Tan, CEO | GRAB | $29.9M | $2.89 | −3.3% |
| Paine Schwartz fund | SUJA | $29.0M | $8.45 | +16.4% |
| Ernest Rady | AAT | $20.1M | $22.57 | −5.3% |
| Top 10 | $2,825.9M | 5 above |
Method
Monk.trade summed the open-market purchases (transaction code P) reported on Form 4 for every actively traded US-listed common stock in the 63 sessions to the Oct 23, 2026 close, and ranked the totals. Each of the largest was then checked against its Form 4s on sec.gov and split by buyer.
A buyer’s average price is the dollar value of its purchases in the window divided by the shares bought, at the prices its Form 4s report. Lennar counts Berkshire Hathaway’s Class A purchases; its $8.8M of Class B is left out. The comparison is with the regular-session close on Oct 23, 2026.
Three totals are left out: MapLight Therapeutics, whose largest purchase matched a private placement’s price and date; Bluerock Private Real Estate Fund, a closed-end fund that director Ramin Kamfar bought through entities he controls; and Aura Minerals, where Bruno Mauad bought $22.7M but sold $119.3M of the stock.
Limits
- Cascade, Berkshire Hathaway, Nippon Life, Conifer, Baker Bros. and the Paine Schwartz fund are 10% owners, insiders under Section 16 of the Securities Exchange Act; Felix Baker is a Kodiak director, and the other Baker Bros. reporting persons are directors by deputization. Ryan Cohen and Anthony Tan are chief executives, Ernest Rady is executive chairman and a 10% owner, and Tor Olav Trøim is a director.
- Context the table hides: Blackstone sold $491.1M of Corebridge on Aug 10, a month before Nippon Life began buying under a Rule 10b5-1 plan adopted Aug 7; Kodiak rose 109% over the window, and Group 1 Automotive fell 27% over the window.
- A Form 4 reports trades up to two business days after they happen and says nothing about why they were made. A price above or below a buyer’s average is not a return on its whole position.
- Figures are as of the Oct 23, 2026 close. Rerunning the query later reads a newer 63-session window. This page is a dated issue; next month’s ranking will be a new page.
Sources
Research only. Not investment advice. Read the risk notice
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