Mills Kenneth T. 4

What Happened

• Kenneth T. Mills, a director of REGENXBIO (RGNX), exercised options to acquire 225,000 shares on 2026-01-27. The exercise shows 225,000 shares acquired at $13.09 per share (value ≈ $2,945,250).
• To satisfy the exercise price and tax withholding, 221,753 shares were withheld/disposed at an effective price of $13.41 per share (value ≈ $2,973,708). After withholding, Mills retained a net 3,247 shares (225,000 − 221,753). No open-market sale was involved.

Key Details

• Transaction dates and amounts:
  • 2026-01-27: Option exercise — 225,000 shares @ $13.09 (acquired), total ≈ $2,945,250.
  • 2026-01-27: Tax/exercise withholding — 221,753 shares @ $13.41 (disposed), total ≈ $2,973,708.
  • Filing date: 2026-01-29 (timely; Form 4 filed within the required window).
• Shares owned after transaction: Not reported in the provided data; net shares retained from this exercise = 3,247.
• Footnotes of note:
  • The option was originally granted Jan 28, 2016, vested over time (25% on Jan 28, 2017, remainder monthly over 36 months) and was set to expire Jan 28, 2026.
  • The 221,753-share disposition represents shares withheld to cover the exercise price and taxes; the number withheld was calculated using the closing price on Jan 27, 2026. No open-market sale occurred.
• Transaction codes: M = option exercise/conversion; F = shares withheld for taxes/exercise price.

Context

• This was effectively a cashless/net-share settlement of an option exercise: the reporting person exercised options and had most of the resulting shares withheld to cover costs and tax obligations, leaving a small net share increase (3,247 shares).
• Such withholding transactions are common at option expiration and do not necessarily signal a buying or selling intent in the open market. They differ from open-market sales where shares are sold to third parties.