SCHEDULE: ARCH Venture Partners Discloses 13.9% Stake in Lyell

ARCH Venture Partners and affiliated entities have reported a 13.9% beneficial ownership stake in Lyell Immunopharma, Inc.

Summary

• ARCH Venture Partners and its affiliated funds (ARCH Venture Fund IX, IX Overage, and XIII) collectively report beneficial ownership of 3,247,162 shares of Lyell Immunopharma, Inc. common stock.
• This holding represents a 13.9% stake in the company based on 23,334,087 shares outstanding as of May 1, 2026.
• The filing identifies multiple managing directors and investment committee members who share voting and dispositive power over these shares.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral regulatory disclosure confirming the existing institutional ownership structure without indicating new strategic shifts.

Positives

• Significant institutional backing from a prominent venture capital firm, signaling long-term confidence in the issuer's business model.

Negatives

• Concentrated ownership by a single venture capital group may lead to potential volatility if the firm decides to divest its position.

Risks

• The reporting persons maintain shared power to dispose of a large block of shares, which could impact market liquidity or share price if sold in large volumes.

Future Outlook

Not applicable as this is a beneficial ownership disclosure filing.

Industry Context

StockSavvy.ai notes that large-scale venture capital ownership is common in the biotechnology sector, where early-stage investors often maintain significant stakes through clinical development phases to support long-term value creation.

Comparison to Industry Standards

• The 13.9% stake is consistent with typical venture capital ownership levels in mid-stage biotech companies.
• The filing structure follows standard SEC reporting requirements for institutional investors under Rule 13d.

Stakeholder Impact

• Shareholders should note the high concentration of ownership, which may influence future corporate governance and voting outcomes.

Next Steps

• The reporting persons will continue to monitor their investment and may file future amendments if their ownership percentage changes significantly.

Key Dates

Keywords

Lyell Immunopharma, ARCH Venture Partners, 13G, Beneficial Ownership, Biotech, Institutional Investor