SEC ownership of SELLAS Life Sciences Group, Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001390478.

Comparable stake leader

STATE STREET CORP

Disclosed value leader

BlackRock, Inc.

Comparable rows

50/50

Latest evidence

30 Jun 2026

Top shareholders Insider holders Latest transactions

Public ticker: SLS on Nasdaq
Parsed ownership sources: 13F and 13D/G
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder: STATE STREET CORP
Ranking: Comparable ownership first, then disclosed value
Comparable ownership rows: 50 of 50
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder: STATE STREET CORP
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date: 30 Jun 2026
Freshness: Most recent filing date in this holder set
Issuer CIK: 0001390478
Issuer location: New York, NY

Ownership snapshot

Top shareholders of SELLAS Life Sciences Group, 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

STATE STREET CORP

Disclosed value leader

BlackRock, Inc.

Comparable rows

50/50

Latest evidence

30 Jun 2026

13F 13D/G Lead comparable stake: 7% 13D/G row: STATE STREET CORP Showing 1-8 of 50 holder rows.

Quick read

STATE STREET CORP leads the comparable SEC ownership view at 7%.

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 STATE STREET CORP's linked filing trail.

Comparable ownership Top 5

STATE STREET CORP 7%

BlackRock, Inc. 6.8%

VANGUARD CAPITAL MANAGEMENT LLC 5.2%

Anson Funds Management LP 4.9%

HIGHBRIDGE CAPITAL MANAGEMENT LLC 3.7%

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
STATE STREET CORP	13F 13D/G Company · STATE STREET CORPORATION 13F 13D/G	7% from 13D/G	$191,829,196 12,996,558 shares	—	30 Jun 2026
BlackRock, Inc.	13F 13D/G Company 13F 13D/G	6.8% from 13D/G	$222,437,657 15,070,302 shares	—	30 Jun 2026
VANGUARD CAPITAL MANAGEMENT LLC	13D/G 13F Vanguard Capital Management · Company 13D/G 13F	5.2%	$121,988,428 9,666,278 shares	$0	30 Jun 2026
Anson Funds Management LP	13F 13D/G Company 13F 13D/G	4.9% from 13D/G	$66,420,000 4,500,000 shares	—	30 Jun 2026
HIGHBRIDGE CAPITAL MANAGEMENT LLC	13D/G 13F Company 13D/G 13F	3.7%	$24,560,261 6,514,658 shares	$0	31 Dec 2025
GEODE CAPITAL MANAGEMENT, LLC	13F Company 13F	2.6%	$72,107,010 4,884,175 shares	—	30 Jun 2026
JONES FINANCIAL COMPANIES LLLP	13F Company 13F	1.2%	$28,553,511 2,304,561 shares	—	30 Jun 2026
VANGUARD PORTFOLIO MANAGEMENT LLC	13F Company 13F	1.2%	$31,897,821 2,161,099 shares	—	30 Jun 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: +$100,806.

Buys

$100,806

Insiders: 1

Sells

Insiders: 0

Net

+$100,806

Shares: +63,400

Window

Last 12 months

4 rolling buckets

Buy value Sell value

Shares: 63,400 Shares: 0

Window (months)	Buy shares	Buy value	Sell value	Net value
0-3	0	$0	$0	$0
3-6	0	$0	$0	$0
6-9	63,400	$100,806	$0	+$100,806
9-12	0	$0	$0	$0

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-10 of 10 reporting-owner rows connected to SELLAS Life Sciences Group, Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows

Largest Forms 3/4/5 holder

Angelos M. Stergiou

Net 12M change

+$100,806

Latest report

16 Jun 2026

Name	Relationship	Holdings Value	Past Year Net Change	Change %	Valuation	Report Date
Angelos M. Stergiou	President and CEO, Director	$7,441,344			Mixed	16 Jun 2026
Dragan Cicic	SVP, Chief Development Officer	$2,102,590			Mixed	07 Jan 2026
John Thomas Burns	Cfo	$2,089,480			Mixed	07 Jan 2026
Barbara A. Wood	EVP, Gen. Counsel, Corp. Sec.	$821,565			Mixed	22 Jan 2024
Katherine Bach Kalin	Director	$581,995	+$100,806	+21%	Mixed	07 Jan 2026
Jane Wasman	Director	$350,177			Mixed	07 Jan 2026
Robert L. van Nostrand	Director	$312,483			Mixed	07 Jan 2026
Robert Francomano	Chief Commercial Officer	$278,365			Mixed	22 Jan 2024
David A. Scheinberg	Director	$275,475			Mixed	07 Jan 2026
John Varian	Director	$274,789			Mixed	07 Jan 2026

Recent insider transactions for SELLAS Life Sciences Group, 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
Angelos M. Stergiou	SLS	Common Stock	Award	153.4%			1,065,000	1,759,183	16 Jun 2026	Direct
John Varian	SLS	Common Stock	Award	218.3%			50,000	72,900	07 Jan 2026	Direct
Robert L. van Nostrand	SLS	Common Stock	Award	152%			50,000	82,900	07 Jan 2026	Direct
David A. Scheinberg	SLS	Common Stock	Award	216.6%			50,000	73,082	07 Jan 2026	Direct
Dragan Cicic	SLS	Common Stock	Award	116.4%			300,000	557,805	07 Jan 2026	Direct
John Thomas Burns	SLS	Common Stock	Award	118%			300,000	554,327	07 Jan 2026	Direct
Katherine Bach Kalin	SLS	Common Stock	Award	47.9%			50,000	154,400	07 Jan 2026	Direct
Jane Wasman	SLS	Common Stock	Award	116.6%			50,000	92,900	07 Jan 2026	Direct
Dragan Cicic	SLS	Common Stock	Other	-19.8%			-63,800	257,805	03 Dec 2025	Direct
John Thomas Burns	SLS	Common Stock	Other	-18.7%			-58,592	254,327	03 Dec 2025	Direct
Angelos M. Stergiou	SLS	Common Stock	Other	-21.4%			-187,066	686,966	03 Dec 2025	Direct
Katherine Bach Kalin	SLS	Common Stock	Purchase	154.6%	$100,806	$1.59	63,400	104,400	19 Nov 2025	Direct

^* marks a reported price that did not pass the local price check.