Comparable stake leader
Fairmount Funds Management LLC
SEC ownership of CRESCENT BIOPHARMA, INC.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001253689.
Disclosed value leader
FMR LLC
Comparable rows
50/50
Latest evidence
31 Mar 2026
- Public ticker
- CBIO on Nasdaq
- Parsed ownership sources
-
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
Fairmount Funds Management LLC
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
Fairmount Funds Management LLC
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
31 Mar 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001253689
- Issuer location
- Waltham, MA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of CRESCENT BIOPHARMA, INC. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Fairmount Funds Managemen...
Disclosed value leader
FMR LLC
Comparable rows
50/50
Latest evidence
31 Mar 2026
13D/G
3/4/5
13F
Lead comparable stake: 19%
13D/G row: Fairmount Funds Management LLC
Showing 1-8 of 50 holder rows.
Quick read
Fairmount Funds Management LLC leads the comparable SEC ownership view at 19%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Fairmount Funds Management LLC's linked filing trail.
Comparable ownership
Top 5
Fairmount Funds Management LLC
19%
FMR LLC
15%
1Globe Capital LLC
10%
BIOTECHNOLOGY VALUE FUND L P
10%
Venrock Healthcare Capital Partne...
9.5%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Fairmount Funds Management LLC |
13D/G
3/4/5
13F
Director, 10%+ Owner · Company
|
19%
|
$73,252,396
5,643,482 shares
|
+$32,700,021 | 04 Dec 2025 |
| FMR LLC |
13F
13D/G
Company
|
15%
from 13D/G
|
$75,932,653
4,133,514 shares
|
— | 31 Mar 2026 |
| 1Globe Capital LLC |
13D/G
|
10%
|
$20,839,816
1,425,432 shares
|
+$7,729,886 | 07 Oct 2025 |
| BIOTECHNOLOGY VALUE FUND L P |
13D/G
BVF PARTNERS L P/IL
|
10%
|
$18,736,150
1,387,863 shares
|
$0 | 30 Jun 2025 |
| Venrock Healthcare Capital Partners III, L.P. |
13D/G
|
9.5%
|
$29,460,007
2,666,064 shares
|
$0 | 31 Dec 2025 |
| ForGrowth III PA B.V. |
13D/G
|
6.1%
|
$21,778,519
1,677,852 shares
|
$0 | 08 Dec 2025 |
| BALYASNY ASSET MANAGEMENT L.P. |
13D/G
13F
Company
|
5.5%
|
$29,294,640
1,510,033 shares
|
$0 | 31 Mar 2026 |
| Vestal Point Capital, LP |
13F
13D/G
Company
|
5.4%
from 13D/G
|
$27,555,000
1,500,000 shares
|
— | 31 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to buying over the last 12 months. Net value: +$18,773,872.
Buys
$19,999,999
Insiders: 1
Sells
$1,226,126
Insiders: 7
Net
+$18,773,872
Shares: +1,423,278
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 1,491,434
Shares: 68,156
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 68,156 | $0 | $1,226,126 | -$1,226,126 |
| 3-6 | 0 | 0 | $0 | $0 | $0 |
| 6-9 | 1,491,434 | 0 | $19,999,999 | $0 | +$19,999,999 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-20 of 34 reporting-owner rows connected to CRESCENT BIOPHARMA, INC.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
34
Largest Forms 3/4/5 holder
Fairmount Funds Management LLC
Net 12M change
+$18,773,872
Latest report
22 Jun 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Fairmount Funds Management LLC | Director, 10%+ Owner | $60,557,872 | +$19,999,999 | +49% | Filing P/S | 02 Jun 2026 |
| Scott D. Sandell | 10%+ Owner | $5,279,783 | Mixed | 25 Jan 2023 | ||
| Joshua T. Brumm | Chief Executive Officer, Director | $5,059,003 | -$761,067 | -13% | Filing P/S | 22 Jun 2026 |
| Jonathan McNeill | President and COO | $2,503,452 | -$369,677 | -13% | Filing P/S | 22 Jun 2026 |
| Siren, L.L.C. | 10%+ Owner | $2,294,139 | Mixed | 25 Jul 2024 | ||
| Rachel K. King | Director | $1,545,582 | Mixed | 01 May 2024 | ||
| Invus Public Equities, L.P. | 10%+ Owner | $1,211,077 | Filing P/S | 07 Aug 2024 | ||
| Christopher Grant Doughty | Chief Business Officer | $937,885 | Mixed | 15 Dec 2025 | ||
| John L. Magnani | SVP of Research, CSO | $875,378 | Mixed | 11 Nov 2022 | ||
| Jan Pinkas | Chief Scientific Officer | $400,079 | -$23,171 | -5.5% | Filing P/S | 22 Jun 2026 |
| Ellie Eunkyung Im | Chief Medical Officer | $397,021 | -$21,930 | -5.2% | Filing P/S | 22 Jun 2026 |
| Chinmaya Rath | SVP and Chief Business Officer | $380,380 | Mixed | 12 Jan 2024 | ||
| Richard William Scalzo | Chief Financial Officer | $365,161 | -$20,005 | -5.2% | Filing P/S | 22 Jun 2026 |
| Barbara Harlin Bispham | General Counsel and Corporate Secretary. | $347,746 | -$21,912 | -5.9% | Filing P/S | 22 Jun 2026 |
| Bruce S. Johnson | SVP & Chief Commercial Officer | $327,993 | Mixed | 12 Jan 2024 | ||
| Daniel M. Junius | Director | $295,377 | Mixed | 01 May 2024 | ||
| Ryan Lynch | Treasurer, Senior Vice President of Finance and Chief Accounting Officer. | $249,539 | -$8,365 | -3.2% | Filing P/S | 22 Jun 2026 |
| Edwin Rock | Chief Medical Officer | $181,736 | Filing P/S | 20 Jun 2024 | ||
| Patricia S. Andrews | Director | $138,315 | Mixed | 01 May 2024 | ||
| Mark Alan Goldberg | Director | $108,975 | Mixed | 01 May 2024 |
Recent insider transactions for CRESCENT BIOPHARMA, INC.
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Ryan Lynch | CBIO | Ordinary Shares | Sale | -3.24% | $8,365 | $17.99 | -465 | 13,871 | 22 Jun 2026 | Direct |
| Jan Pinkas | CBIO | Ordinary Shares | Sale | -5.47% | $23,171 | $17.99 | -1,288 | 22,239 | 22 Jun 2026 | Direct |
| Richard William Scalzo | CBIO | Ordinary Shares | Sale | -5.19% | $20,005 | $17.99 | -1,112 | 20,298 | 22 Jun 2026 | Direct |
| Barbara Harlin Bispham | CBIO | Ordinary Shares | Sale | -5.93% | $21,912 | $17.99 | -1,218 | 19,330 | 22 Jun 2026 | Direct |
| Ellie Eunkyung Im | CBIO | Ordinary Shares | Sale | -5.23% | $21,930 | $17.99 | -1,219 | 22,069 | 22 Jun 2026 | Direct |
| Jonathan McNeill | CBIO | Ordinary Shares | Sale | -12.9% | $369,677 | $17.99 | -20,549 | 139,158 | 22 Jun 2026 | Direct |
| Joshua T. Brumm | CBIO | Ordinary Shares | Sale | -13.1% | $761,067 | $17.99 | -42,305 | 281,212 | 22 Jun 2026 | Direct |
| Jonathan Violin | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | Direct | |||
| David Charles Lubner | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | Direct | |||
| Alexandra Balcom | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | Direct | |||
| Susan Moran | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | Direct | |||
| Fairmount Funds Management LLC | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | By: Peter Harwin | |||
| Fairmount Funds Management LLC | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | By: Peter Harwin | |||
| Fairmount Funds Management LLC | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | By: Peter Harwin | |||
| Fairmount Funds Management LLC | CBIO | Stock Option (Right to Buy) | Award | 11,050 | 11,050 | 02 Jun 2026 | By: Peter Harwin | |||
| Jan Pinkas | GLYC | Ordinary Shares | Award | 22,507 | 22,507 | 15 Dec 2025 | Direct | |||
| Jan Pinkas | GLYC | Stock Option (Right to Buy) | Award | 70,025 | 70,025 | 15 Dec 2025 | Direct | |||
| Christopher Grant Doughty | GLYC | Ordinary Shares | Award | 57.5% | 22,714 | 62,194 | 15 Dec 2025 | Direct | ||
| Christopher Grant Doughty | GLYC | Stock Option (Right to Buy) | Award | 58,855 | 58,855 | 15 Dec 2025 | Direct | |||
| Joshua T. Brumm | GLYC | Ordinary Shares | Award | 20.5% | 55,117 | 323,517 | 15 Dec 2025 | Direct | ||
| Joshua T. Brumm | GLYC | Stock Option (Right to Buy) | Award | 180,467 | 180,467 | 15 Dec 2025 | Direct | |||
| Richard William Scalzo | GLYC | Ordinary Shares | Award | 19,422 | 19,422 | 15 Dec 2025 | Direct | |||
| Richard William Scalzo | GLYC | Stock Option (Right to Buy) | Award | 57,688 | 57,688 | 15 Dec 2025 | Direct | |||
| Jonathan McNeill | GLYC | Ordinary Shares | Award | 19% | 25,507 | 159,707 | 15 Dec 2025 | Direct | ||
| Jonathan McNeill | GLYC | Stock Option (Right to Buy) | Award | 78,029 | 78,029 | 15 Dec 2025 | Direct | |||
| Ellie Eunkyung Im | GLYC | Ordinary Shares | Award | 21,298 | 21,298 | 15 Dec 2025 | Direct | |||
| Ellie Eunkyung Im | GLYC | Stock Option (Right to Buy) | Award | 65,190 | 65,190 | 15 Dec 2025 | Direct | |||
| Ryan Lynch | GLYC | Ordinary Shares | Award | 12,378 | 12,378 | 15 Dec 2025 | Direct | |||
| Ryan Lynch | GLYC | Stock Option (Right to Buy) | Award | 33,512 | 33,512 | 15 Dec 2025 | Direct | |||
| Barbara Harlin Bispham | GLYC | Ordinary Shares | Award | 18,422 | 18,422 | 15 Dec 2025 | Direct | |||
| Barbara Harlin Bispham | GLYC | Stock Option (Right to Buy) | Award | 72,185 | 72,185 | 15 Dec 2025 | Direct | |||
| Jonathan McNeill | GLYC | Stock Option (Right to Buy) | Award | 172,836 | 172,836 | 08 Dec 2025 | Direct | |||
| Joshua T. Brumm | GLYC | Stock Option (Right to Buy) | Award | 345,672 | 345,672 | 08 Dec 2025 | Direct | |||
| Fairmount Funds Management LLC | GLYC | Ordinary Shares | Purchase | 98% | $18,237,600 | $13.41 | 1,360,000 | 2,747,866 | 04 Dec 2025 | By Fairmount Healthcare Fund II L.P. |
| Fairmount Funds Management LLC | GLYC | Pre-Funded Warrant (Right to Buy) | Purchase | 8.03% | $1,762,399 | $13.41 | 131,434 | 1,768,140 | 04 Dec 2025 | By Fairmount Healthcare Fund II L.P. |
| Jan Pinkas | GLYC | Stock Option (Right to Buy) | Award | 142,474 | 142,474 | 16 Jul 2025 | Direct |
* marks a reported price that did not pass the local price check.