Twist Bioscience CEO Emily Leproust Files Form 144 to Sell 4,548 Shares Under 10b5-1 Plan

Executive Summary

On October 5, 2026, Emily M. Leproust, CEO and Director of Twist Bioscience Corp ($TWST), filed a Form 144 notice of proposed sale covering 4,548 shares of common stock with an aggregate market value of approximately $919,373.72 (implied price of ~$202.15 per share). The proposed sale is executed pursuant to a Rule 10b5-1 trading plan adopted on June 15, 2026.

Transaction & Securities Details

• Securities to be Sold: 4,548 shares of Common Stock
• Aggregate Market Value: $919,373.72
• Shares Outstanding: 62,707,424
• Percentage of Outstanding: ~0.007%
• Acquisition Source: Acquired directly from the issuer via restricted stock vesting across multiple tranches between June 19, 2026, and September 19, 2026 as compensation.
• Broker: Fidelity Brokerage Services LLC

Prior 3-Month Sales Activity

The filing discloses extensive sales activity by Dr. Leproust over the preceding three months under her Rule 10b5-1 plan, totaling over 589,000 shares across multiple transactions since August 2026.

Trading Significance

The trading significance is assessed as Low. The proposed sale represents a negligible fraction of the company's outstanding shares (<0.01%) and is conducted under a pre-established Rule 10b5-1 plan adopted in June 2026, routine for executive equity compensation monetization.