RICCIARDI NATALE S 4

What Happened
Natale S. Ricciardi, a director of Rapid Micro Biosystems, exercised stock options covering 842 shares at an exercise price of $0.75 per share (total cost/value $632) on February 27, 2026. The Form 4 also records a simultaneous disposal of a derivative instrument for the same 842-share amount, so there was no net increase in listed shares owned after these entries.

Key Details

• Transaction date: 2026-02-27; Form 4 filed: 2026-03-02 (filed within required timeframe).
• Exercise details: 842 shares exercised at $0.75 per share; total $632.
• Disposal details: 842 shares listed as disposed (derivative) at $0.75; net change in reported shares = zero (842 acquired, 842 disposed).
• Shares owned after transaction: not separately reported in the provided filing excerpt.
• Footnote: F1 — the option exercised was fully vested and exercisable.
• No 10b5-1 plan, tax withholding, or separate open-market sale price was disclosed in the provided data.

Context
This was an option exercise (derivative transaction). Because the same number of shares were recorded as acquired and disposed, the filing indicates the exercise did not increase the director’s reported shareholding — a common outcome when exercises are paired with sales to cover costs or taxes. Exercises are routine for insiders with vested options and do not by themselves signal a buy/sell opinion.