Cerebras Systems CTO Sean Lie Exercises Options and Sells $25.1M in Stock Under 10b5-1 Plan

Executive Summary

On September 28, 2026, Cerebras Systems Inc. (NASDAQ: CBRS) filed a Form 4 disclosing significant activity by its Chief Technology Officer, Sean Lie. On September 25, 2026, Lie exercised 120,000 stock options at strike prices of $5.02 and $5.48, converted the resulting Class B shares into Class A Common Stock, and sold all 120,000 shares via open-market transactions for aggregate proceeds of approximately $25.08 million.

In addition, Lie completed a charitable gift of 36,000 Class A shares to a 501(c)(3) donor-advised fund.

Transaction Details

• Stock Option Exercises (Code M):

  • Exercised 116,875 options at $5.48/share for Class B Common Stock (expires 2034).
  • Exercised 3,125 options at $5.02/share for Class B Common Stock (expires 2033).
  • Total option exercise cost: ~$656,162.50.

• Conversion (Code C):

  • Converted 120,000 Class B shares to Class A Common Stock on a 1:1 basis.

• Open-Market Sales (Code S):

  • Total Shares Sold: 120,000 Class A shares across 9 price tranches ranging from $203.86 to $212.31.
  • Weighted Average Sale Price: ~$208.97.
  • Total Value Realized: $25,076,264.28.
  • Execution Plan: Executed pursuant to a pre-arranged Rule 10b5-1 trading plan adopted on May 20, 2026.

• Charitable Gift (Code G):

  • Transferred 36,000 shares to a donor-advised fund sponsored by a 501(c)(3) organization.

Holdings Analysis

Following these transactions, Sean Lie continues to maintain substantial skin in the game:

• Direct Ownership (Class A): 309,569 shares.
• Direct Ownership (Class B): 7,582,992 shares (convertible 1:1 into Class A Common Stock).
• Indirect Ownership (Class B): 180,600 shares held by spouse.
• Remaining Derivative Holdings: 204,566 unexercised stock options across the two grant series.

The 120,000-share disposition represents less than 2% of Lie's total equity stake in Cerebras Systems, indicating that this transaction primarily served as liquidity/tax diversification under a structured trading plan rather than a lack of confidence in the company's prospects.