Key points
- Aspen Neuroscience, Inc. insiders bought $68.00 million of stock, most recently on November 2nd, 2026.
- Bambusa Therapeutics, Inc. insiders bought $58.64 million of stock, most recently on November 2nd, 2026.
- Lyell Immunopharma, Inc. insiders bought $50.00 million of stock, most recently on November 4th, 2026.
For October 10th, 2026 to November 9th, 2026, biotech as measured by XBI returned 1.4% while the S&P 500 returned -2.9%, per index price data, a spread of 4.4% in favour of the sector. The purchase screen returned 6 names carrying 36 Form 4 filings from 18 distinct filers and $199.7 million of open-market buying across 13,945,891 shares, and the point of that result is that it tests filings rather than price action.
The backdrop
The U-6 unemployment rate for October printed 8 in the Bureau of Labor Statistics release dated November 6th, 2026, unchanged against a previous reading of 8. The mechanism for biotech runs through the rate path: a labour market that is neither tightening nor loosening gives the Federal Reserve no reason to move quickly, and the discount rate applied to cash flows that sit years beyond a clinical readout is the single largest input into valuations for pre-revenue developers. That matters more here than in most sectors, because the companies on this list fund themselves by issuing equity rather than from operations, so the cost of capital sets the terms on which research continues. Against that backdrop, net insider flow across the sector in the window was $-146.3 million on 11,251,351 shares, which means the buying described below sat inside a sector where sales still outweighed purchases in dollar terms.
| Insider | Role | Date | Shares | Price | Value | Filing date |
|---|---|---|---|---|---|---|
| Aspen Neuroscience, Inc. (ASPE) | ||||||
| ARCH Venture Partners XIV, L.P. | Other | November 2nd, 2026 | 1,200,000 | $15.00 | $18.00 million | November 2nd, 2026 |
| ARCH Venture Fund X, L.P. | Other | November 2nd, 2026 | 1,200,000 | $15.00 | $18.00 million | November 2nd, 2026 |
| ORBIMED ADVISORS LLC | Director | November 2nd, 2026 | 1,000,000 | $15.00 | $15.00 million | November 4th, 2026 |
| Thompson Peter A. | Director | November 2nd, 2026 | 1,000,000 | $15.00 | $15.00 million | November 4th, 2026 |
| Bambusa Therapeutics, Inc. (BBTX) | ||||||
| RA CAPITAL MANAGEMENT, L.P. | Director | November 2nd, 2026 | 2,335,109 | $16.00 | $37.36 million | November 3rd, 2026 |
| Jeggle Helmut Wolfgang | Director | November 2nd, 2026 | 375,000 | $16.00 | $6.00 million | November 2nd, 2026 |
| Salvia Investment GmbH | Other | November 2nd, 2026 | 375,000 | $16.00 | $6.00 million | November 2nd, 2026 |
| RA CAPITAL MANAGEMENT, L.P. | Director | November 2nd, 2026 | 164,891 | $16.00 | $2.64 million | November 3rd, 2026 |
| Lyell Immunopharma, Inc. (LYEL) | ||||||
| ARCH Venture Fund XIII, L.P. | Other | November 4th, 2026 | 2,321,262 | $10.77 | $25.00 million | November 5th, 2026 |
| ARCH Venture Partners IX, LLC | Other | November 4th, 2026 | 2,321,262 | $10.77 | $25.00 million | November 5th, 2026 |
| Rapport Therapeutics, Inc. (RAPP) | ||||||
| HEALY JAMES | Director | October 28th, 2026 | 952,380 | $21.00 | $20.00 million | October 30th, 2026 |
| HEALY JAMES | Director | October 28th, 2026 | 6,933 | $21.00 | $145,593 | October 30th, 2026 |
| HEALY JAMES | Director | October 28th, 2026 | 6,395 | $21.00 | $134,295 | October 30th, 2026 |
| HEALY JAMES | Director | October 28th, 2026 | 3,772 | $21.00 | $79,212 | October 30th, 2026 |
| Inhibrx Biosciences, Inc. (INBX) | ||||||
| Lappe Mark | Chief Executive Officer | October 14th, 2026 | 2,470 | $85.00 | $209,948 | October 14th, 2026 |
| Lappe Mark | Chief Executive Officer | October 14th, 2026 | 2,451 | $85.00 | $208,333 | October 14th, 2026 |
| Lappe Mark | Chief Executive Officer | October 14th, 2026 | 2,470 | $84.07 | $207,655 | October 14th, 2026 |
| Lappe Mark | Chief Executive Officer | October 14th, 2026 | 2,449 | $84.07 | $205,889 | October 14th, 2026 |
| AgomAb Therapeutics NV (AGMB) | ||||||
| Epstein David R | Director | November 5th, 2026 | 5,000 | $6.98 | $34,900 | November 6th, 2026 |
| Epstein David R | Director | November 5th, 2026 | 5,000 | $6.91 | $34,550 | November 6th, 2026 |
| Epstein David R | Director | November 5th, 2026 | 5,000 | $6.81 | $34,050 | November 6th, 2026 |
| Epstein David R | Director | October 21st, 2026 | 5,000 | $8.90 | $44,500 | October 22nd, 2026 |
| Benchmark return, same period | XBI versus the S&P 500 | October 10th, 2026 to November 9th, 2026 | n/a | 1.4% | n/a | VERIFY |
Aspen Neuroscience, Inc. (ASPE)
Aspen Neuroscience, Inc. (ASPE) drew $68.00 million of open-market purchases from 4 distinct filers across 6 purchases, with the first and most recent filing both dated November 2nd, 2026. ARCH Venture Partners XIV, L.P. and ARCH Venture Fund X, L.P., each filing in an Other capacity, bought 1,200,000 shares apiece at $15.00 for $18.00 million each, while ORBIMED ADVISORS LLC and director Peter A. Thompson each took 1,000,000 shares at $15.00 for $15.00 million. Every ticket cleared at the same $15.00 print on the same day, which is the profile of a coordinated allocation rather than opportunistic accumulation, and it landed in a sector that outperformed the S&P 500 by 4.4% over the window.
Bambusa Therapeutics, Inc. (BBTX)
Bambusa Therapeutics, Inc. (BBTX) saw $58.64 million bought by 3 distinct filers over 6 purchases, beginning October 30th, 2026 and ending November 2nd, 2026. RA CAPITAL MANAGEMENT, L.P., filing as a director, took 2,335,109 shares at $16.00 for $37.36 million and a further 164,891 shares at $16.00 for $2.64 million. Director Helmut Wolfgang Jeggle and Salvia Investment GmbH each bought 375,000 shares at $16.00 for $6.00 million. The uniform $16.00 price across all four tickets again points to a single pricing event rather than a series of market fills.
Lyell Immunopharma, Inc. (LYEL)
Lyell Immunopharma, Inc. (LYEL) recorded $50.00 million from 2 filers in 2 purchases, both dated November 4th, 2026 and filed November 5th, 2026. ARCH Venture Fund XIII, L.P. and ARCH Venture Partners IX, LLC, both filing in an Other capacity, each bought 2,321,262 shares at $10.77 for $25.00 million. Two filings, one price, identical size: the symmetry is the information here, and it arrived in the same week as the Aspen Neuroscience tickets from related ARCH entities.
Rapport Therapeutics, Inc. (RAPP)
Rapport Therapeutics, Inc. (RAPP) produced the broadest participation on the list, with 7 distinct filers and 11 purchases totalling $22.02 million between October 21st, 2026 and October 28th, 2026. Director James Healy accounted for the bulk, buying 952,380 shares at $21.00 for $20.00 million, alongside smaller tickets of 6,933 shares for $145,593, 6,395 shares for $134,295 and 3,772 shares for $79,212, each at $21.00. The mix of one large block and several small ones at a single price is the pattern a professional reader can test against the sector return of 1.4% over the same window.
Inhibrx Biosciences, Inc. (INBX)
Inhibrx Biosciences, Inc. (INBX) stands apart as a single-filer name: Chief Executive Officer Mark Lappe accounted for all $848,977 across 6 purchases on October 14th, 2026. The tickets were 2,470 shares at $85.00 for $209,948, 2,451 shares at $85.00 for $208,333, 2,470 shares at $84.07 for $207,655 and 2,449 shares at $84.07 for $205,889. Two distinct fill prices and near-identical lot sizes suggest an executed order worked through the market rather than a negotiated placement, which is a different signal from the block buying elsewhere on this list.
AgomAb Therapeutics NV (AGMB)
AgomAb Therapeutics NV (AGMB) is the smallest entry, with $192,300 from 1 filer across 5 purchases spanning October 21st, 2026 to November 5th, 2026. Director David R Epstein bought 5,000 shares at $8.90 for $44,500 on October 21st, 2026, then three further lots of 5,000 shares on November 5th, 2026 at $6.98, $6.91 and $6.81 for $34,900, $34,550 and $34,050. Buying at successively lower prices over two weeks is the one genuinely incremental pattern in the group, and it occurred while the sector itself returned 1.4%.
What would change the view
- The next U-6 unemployment reading from the Bureau of Labor Statistics: the October print held at 8 against a previous 8 on November 6th, 2026, and a move away from that level would change the rate assumption underpinning long-duration biotech valuations.
- Follow-on Form 4 activity at the two freshest names, Lyell Immunopharma with a most recent filing on November 4th, 2026 and AgomAb Therapeutics with a most recent filing on November 5th, 2026: continued purchases would extend the pattern, while disposals from the same filers would undercut it.
Methodology and sources
Screen. CL-01 v1: At least 2 distinct insiders with open-market purchases (code P) within 30 days. Aggregate value at least $250,000.
Data pull. Prices and filings as of November 9th, 2026, covering October 10th, 2026 to November 9th, 2026.
Benchmark. XBI versus the S&P 500, priced on exchange closes over the same dates. Period return is the close on the end date divided by the close on the start date, minus one.
Filing accessions. 0001193125-26-444141, 0001193125-26-444147, 0000947871-26-000980, 0000947871-26-000981, 0001231919-26-001533, 0001982614-26-000004, 0002162499-26-000004, 0001012975-26-001013, 0001012975-26-001014, 0001104659-26-120789, 0001366074-26-000006, 0001445826-26-000018, 0001445826-26-000015
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