🏛️ What This Document Is

This is a Proxy Statement (DEF 14A) for the 2026 Annual Meeting of Stockholders. Think of this document as the annual "instruction manual" that tells you exactly what decisions the company needs the shareholders to approve.

The purpose is twofold: to detail the company's corporate governance structure and, more importantly, to gather votes on critical proposals related to leadership, compensation, and the company's ability to issue stock in the future.

👉 Why it matters: Your vote on these matters dictates the corporate direction, the compensation levels of the executive team, and the financial flexibility of the company for years to come.

🏢 What The Company Does

Assembly Biosciences, Inc. is a life sciences company dedicated to research and development. While the filing does not detail its specific products, the context is clear: the company operates in a highly competitive and capital-intensive sector that requires significant long-term investment in its pipeline.

The company’s overall business strategy is heavily tied to its ability to attract and retain top scientific and executive talent. This continuous talent acquisition is why the annual meetings focus so heavily on executive compensation and equity awards.

👉 Key facts:

• Full Name: Assembly Biosciences, Inc.
• Address: Two Tower Place, 7th Floor South San Francisco, California 94080.
• Industry: Biotechnology/Life Sciences (Inferred from the context of R&D and pipeline candidates).

📋 Meeting Logistics and Voter Instructions

Before discussing the proposals, it is crucial to know how and when the meeting happens. The Annual Meeting is scheduled for Thursday, June 4, 2026, starting at 8:00 a.m. Pacific Daylight Time (PDT).

The company confirms that the meeting will be virtual-only, meaning stockholders cannot attend in person.

👉 Key Dates & Deadlines:

• Record Date: The close of business on April 10, 2026, determines who is entitled to vote.
• Vote Deadline: Votes must be received by 11:59 p.m. Eastern Daylight Time (EDT) on June 3, 2026.
• How to Vote: You can vote virtually (using your 16-digit control number), by phone (using provided toll-free numbers), or by mail (requesting a physical proxy card).

The company reminds all stockholders that they can vote through the Internet at www.proxyvote.com.

🗳️ Governance and Board Oversight

Good corporate governance is the system that ensures the company is run responsibly, protecting shareholder interests. The Board of Directors has detailed its structure to reassure stockholders that oversight is rigorous and independent.

The board structure is managed by independent committees designed to monitor key areas of the business.

👉 Key Governance Points:

• Board Size: The Board will consist of nine directors after the Annual Meeting.
• Independence: Six of the nine nominees are independent under Nasdaq rules.
• Leadership: William R. Ringo, Jr., the current independent Chair, is not standing for re-election. Anthony E. Altig, an independent director, is set to become the new Chair.
• Committees: The Audit, Compensation, and Nominating and Governance Committees are composed entirely of directors who are independent under Nasdaq listing rules.
• Risk Oversight: The full Board is responsible for overseeing risk, balancing the assessment and mitigation of risks, and taking appropriate risk in the business's operation.

👨‍💼 Executive Compensation (Say on Pay)

This section addresses Proposal No. 2, known as the "Say on Pay" vote. This is a non-binding advisory vote allowing stockholders to weigh in on whether they believe the company's executive compensation package is appropriate.

The Board recommends a vote "FOR" approving the Named Executive Officers' (NEO) compensation.

• Philosophy: The company's compensation philosophy is to provide "Competitive Overall Compensation That Attracts, Retains and Motivates Superior Performers."
• Structure: Compensation is designed to be a mix of:
  1. Base Salary (Fixed): Competitive salary based on role.
  2. Annual Performance-based Cash Bonus (Variable): Based on company-wide and individual goals.
  3. Long-Term Equity Incentive Awards (Variable): Used to align executive interests with long-term stock value.
• Historical Insight: The company noted that approximately 79% of votes cast on this proposal were voted in favor in 2025.

🔎 Audit Committee and Independent Auditor

Proposal No. 3 asks stockholders to ratify the selection of the independent public accounting firm for 2026. The Audit Committee reviewed the company's financials and concluded that maintaining independence is key to good corporate practice.

The Audit Committee has selected Ernst & Young LLP to serve as the independent registered public accounting firm for the fiscal year ending December 31, 2026.

👉 Financial Review:

• The Audit Committee reviewed and discussed the audited consolidated financial statements and internal control over financial reporting for the year ended December 31, 2025.
• Fees Paid: For the fiscal year ended December 31, 2025, the aggregate fees paid to Ernst & Young LLP totaled $1,129,050. This is compared to $1,104,973 in 2024.
• Audit Fees: These covered the audit, review, and consultations for the consolidated financial statements.

📈 Proposed Amendment to the Stock Incentive Plan (Proposal 4)

This is arguably the most critical section for current shareholders. Proposal No. 4 seeks to amend the 2018 Stock Incentive Plan by increasing the number of reserved shares by 1,200,000 shares.

The core reason for this request is due to the massive increase in the company's outstanding shares following a major financing event.

👉 The Problem (The "Why"):

• The 2025 Financing (completed in August 2025) significantly increased the outstanding shares by raising approximately $175 million.
• The company's previous annual plan approvals (at the 2025 Annual Meeting) were based on the share count before this financing.
• As of April 10, 2026, the company had 16,933,428 million shares of common stock outstanding (including Pre-Funded Warrants).
• The existing pool of shares available under the 2018 Plan is insufficient to cover current needs, including 203,596 Remaining RSUs and expected 51,000 Board Options.

The Request: The Plan Amendment seeks to increase the reserved shares by 1,200,000 to cover these immediate grants and provide necessary funds for future hiring.

💰 Proposed Amendment to the ESPP (Proposal 5)

Similarly, Proposal No. 5 asks to amend the Second Amended and Restated 2018 Employee Stock Purchase Plan by increasing the shares reserved for issuance by 515,000 shares.

This amendment follows the same logic as the 2018 Plan—that the substantial share count increase from the 2025 Financing requires a proportional increase in reserved shares to maintain the company’s ability to grant competitive equity awards.

📊 Equity Overhang and Financial Position

The concept of "overhang" refers to the large number of shares that are already promised or reserved to employees and directors but haven't been issued yet. This figure is crucial because it shows potential future dilution to common stockholders.

• Current Overhang (As of April 10, 2026): The total overhang is 1,890,508 shares.
• Current Overhang Percentage: This translates to an 11.9% overhang relative to outstanding shares.
• The Impact of Approval: Assuming stockholders approve the 1,200,000 share increase (Proposal 4), the total overhang increases to 3,090,508 shares, resulting in an overhang percentage of 18.3% (including pre-funded warrants).
• Why it matters: The company notes that even the 18.3% figure falls between the 25th and 50th percentile of its peer group, suggesting that the request is aligned with industry norms.

🧭 Corporate Strategy and Future Outlook

Management stressed that the equity compensation programs are not just about pay; they are vital tools for survival and growth in the competitive biotech space.

• Talent Retention: The company states that a skilled workforce is essential for advancing its "pipeline of product candidates." If the Plan Amendments fail, the company warns that it would be difficult to retain key personnel, potentially forcing the replacement of valuable equity grants with cash.
• Sustainability: Management recognizes the importance of "corporate responsibility" and monitoring environmental and social issues, providing a dedicated section on its corporate website for these updates.
• Investor Relations: The company plans to continue targeted stockholder engagement in 2026, particularly focusing on the executive compensation program, with the goal of meeting with all institutional stockholders holding over 1% of stock in 2026.

📧 Contact and Legal Details

Should stockholders have questions, the filing provides specific contact information:

• For proxy materials: The company's Corporate Secretary can be reached by email at [email protected].
• For general information: They encourage calling +1.833.509.4583 to request the Annual Report.
• General Headquarters: Two Tower Place, 7th Floor South San Francisco, California 94080.

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🧠 The Analogy

Voting on a proxy statement is like deciding on a community renovation budget. You don't just vote on the contractor (the independent auditor) or the lead designer (the board). You also vote on the rules of the clubhouse (the Amended Plans). If you don't approve enough new funds (the shares reserved) for the maintenance fund, the building manager (the CEO) might be forced to cut essential services (like giving bonuses in stock) and replace them with cash, which is much harder to manage and might require drastic, unplanned spending (the cash runway).

🧩 Final Takeaway

The company is asking stockholders to approve major increases in reserved shares for two key compensation plans. This is critical because a recent large financing dramatically increased the company's outstanding share count, making the current plans mathematically insufficient to fund necessary employee retention and bonuses.