BVF Partners OS Ltd.

CIK 1660684 · last filed 2025-08-07

BVF Partners OS Ltd. is a corporate insider who has filed 17 SEC Form 4 insider transactions across 13 companies since 2017. The most recent filing, for EPIX, was dated Aug 7, 2025. Across all open-market trades the lifetime net is −$771.2M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $364.7M across reported positions. The firm reports its address in Grand Cayman, E9. 237 SEC filings were submitted jointly with BIOTECHNOLOGY VALUE FUND II LP.

"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.

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Disclosed Exposure

$364.74M

Companies

13

Total Filings

17

Lifetime Open-Market Net

-$771.20M

Filer Profile

Reported Address
P.O. BOX 309 UGLAND HOUSE
GRAND CAYMAN, E9 KY1-1104
Phone
(415) 525-8890
State of Incorporation
Cayman Islands
Related Filers
BIOTECHNOLOGY VALUE FUND II LP — 237 joint filings, latest 2026-07-16
BIOTECHNOLOGY VALUE FUND L P — 237 joint filings, latest 2026-07-16
BVF INC/IL — 237 joint filings, latest 2026-07-16
BVF PARTNERS L P/IL — 237 joint filings, latest 2026-07-16
Biotechnology Value Trading Fund OS LP — 237 joint filings, latest 2026-07-16
MARK N LAMPERT — 237 joint filings, latest 2026-07-16
BVF GP HOLDINGS LLC — 155 joint filings, latest 2026-07-16
BVF I GP LLC — 155 joint filings, latest 2026-07-16
Profile details as reported on the filer's SEC submissions — for individual insiders the address is often in care of the issuer. Related filers are identified from jointly filed SEC submissions and shared reported addresses. View filings on SEC EDGAR.

Holdings By Company

Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
Symbol Role Shares Price Disclosed Exposure Lifetime OM Net Filings Latest Filed
ESSA Pharma Inc. (EPIX) Delisted 4,726,809 $0.20 $951.0K -$2.9K 1 2025-08-07
ELDN 145,029 $2.78 $403.2K $0 1 2023-05-09
CTI BIOPHARMA CORP (CTIC) Delisted Director 62,978 $9.09 $572.5K -$520.20M 1 2022-08-11
Merus N.V. (MRUS) Delisted 311,210 $90.00 $28.01M -$432.55M 2 2021-07-07
Eledon Pharmaceuticals, Inc. (NVUS) Delisted 771,780 $0 1 2020-12-28
OLMA 3,392,663 $10.22 $34.67M $215.71M 1 2020-11-20
XOMA Royalty Corp (XOMA) Delisted 1,941,035 $40.17 $77.97M $5.47M 1 2020-08-25
KYMR 1,359,109 $114.96 $156.24M $0 1 2020-08-25
CYTK 2,350,829 $73.77 $173.42M -$118.47M 1 2020-02-18
FIVE PRIME THERAPEUTICS, INC. (FPRX) Delisted 3,648,474 $38.00 $138.64M $30.45M 2 2019-12-11
INFINITY PHARMACEUTICALS, INC. (INFI) Delisted 5,815,887 $0.04 $260.0K $8.55M 1 2018-11-15
CONCERT PHARMACEUTICALS, INC. (CNCE) Delisted 291,788 $8.37 $2.44M $36.80M 1 2017-10-23
ALPINE IMMUNE SCIENCES, INC. (NVLS) Delisted 163,342 $3.04M 2 2017-05-19

Recent Filings

17 filings
Insider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
Filed Symbol Action Net Shares Net $ Link
2025-08-07 ESSA Pharma Inc. (EPIX) Delisted Mixed +29,198,440 -$10 EDGAR
2023-05-09 ELDN Buy (P) +19,789,320 $0 EDGAR
2022-08-11 CTI BIOPHARMA CORP (CTIC) Delisted Mixed −1,166,690 -$520.20M EDGAR
2021-07-07 Merus N.V. (MRUS) Delisted Sell (S) −21,860,220 -$453.60M EDGAR
2020-12-28 Eledon Pharmaceuticals, Inc. (NVUS) Delisted Conv (C) +12,896,280 $0 EDGAR
2020-11-20 OLMA Mixed +63,520,100 $215.71M EDGAR
2020-09-14 Merus N.V. (MRUS) Delisted Buy (P) +1,896,510 $21.05M EDGAR
2020-08-25 XOMA Royalty Corp (XOMA) Delisted Buy (P) +281,750 $5.47M EDGAR
2020-08-25 KYMR Mixed +25,574,970 $195.74M EDGAR
2020-02-18 CYTK Sell (S) −7,504,210 -$118.47M EDGAR
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Form 4 codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.