SLS Stock In Spotlight After Vanguard Capital Discloses 5.19% Stake – Retail Calls It ‘Huge Vote Of Conviction’ As AML Trial Readout Nears

• Earlier this week, five investors disclosed new positions or increased their stake in Sellas.
• Investors are awaiting final data from Sellas’ Regal Phase 3 trial evaluating Galinpepimut-S in acute myeloid leukemia.
• SLS is on track to record its biggest monthly drop since January 2024.

Sellas Life Sciences Group (SLS) drew investor attention on Friday after a new Schedule 13G filing showed that Vanguard Capital Management has a 5.19% stake in the company.

The filing showed beneficial ownership of 9.67 million shares as of June 30, 2026.

At the time of writing, SLS stock was down 3.5% and is on track to record its biggest monthly slump since January 2024.

Investors Increase Stake

Earlier this week, five investors increased their stakes or took up new positions in the company. ALPS Advisors disclosed a new stake of 188,107 shares valued at about $2.78 million. The New York State Common Retirement Fund increased its holding by 27,300 shares, or 70%, to 66,300 shares worth roughly $979,000.

Swiss Life Asset Management also reported a new position of 12,124 shares valued at about $180,000. Meanwhile, Commonwealth Equity Services raised its stake by 17% to 45,087 shares worth around $665,000, and Axxcess Wealth Management increased its holding by nearly 17% to 41,373 shares valued at about $611,000.

According to Fintel data, 265 institutional investors collectively own around 36.34% of the company’s outstanding shares.

Quiet Period Ahead Of AML Trial Final Trigger

All eyes are now on the Regal Phase 3 trial evaluating Galinpepimut-S (GPS) in acute myeloid leukemia (AML).

The study has recorded 78 of the 80 events (deaths) needed for the final analysis. Because the trial’s main goal is overall survival, CEO Angelos Stergiou has said that the slower rate of events could be a positive sign.

Sellas has said the REGAL trial would be considered successful if GPS improves median survival to 12.6 months, compared with about eight months under standard treatment. With the trial nearing its final analysis, Sellas has entered a quiet period.

Retail Sees Further Institutional Investments

While retail sentiment surrounding SLS on Stocktwits remained ‘neutral’ over the past 24 hours, chatter around the Vanguard stake update was positive.

One user called it a “huge vote of conviction.”

Another user expects further investment updates, adding that the “only way is up!”

SLS shares have climbed around 128% so far this year.

Also read: RIVN Stock Slides Toward Biggest Monthly Drop Since January – Wall Street Flags Profitability Challenges Despite Q2 Beat

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