PEI MELINDA LITHERLAND 4

4 · RAPID MICRO BIOSYSTEMS, INC. · Filed Jun 2, 2026

AI-generated summary of this filing

Updated Jun 2, 2026

Rapid Micro (RPID) Director Melinda L. Pei Buys 12,787 Shares

What Happened

Melinda L. Pei, a director of Rapid Micro Biosystems, purchased 12,787 shares of the company's Class A common stock in a registered direct offering on May 29, 2026. The effective purchase price was $1.955 per share, for a cash outlay of roughly $24,999.
As part of the same transaction she also acquired accompanying Series A and Series B warrants (each covering 12,787 shares or pre-funded warrants in lieu thereof). Those warrants are reported as derivative acquisitions on the Form 4.

Key Details

Transaction date and price: May 29, 2026 — 12,787 shares at $1.955 per share (total ≈ $24,999). Series A and Series B warrants associated with those shares were also acquired as part of the package.
Shares owned after transaction: Not specified in the provided filing (not disclosed here).
Footnotes of note:
- The package (shares + Series A and B warrants) was purchased in a registered direct offering; the unit price per share + associated warrants was $1.955 (F1).
- Exercise limitation: the Series A and B warrants contain a 4.99% beneficial ownership cap — they cannot be exercised if exercise would push the holder above 4.99% of outstanding Class A shares (F2).
- Issuance was approved by the company’s compensation committee under Rule 16b-3 (F1).
Filing timeliness: Form 4 was filed June 2, 2026 for a May 29, 2026 transaction; this appears to be filed within the standard two-business-day window and is timely.

Context

This was a direct purchase of stock with accompanying warrants — a straightforward insider acquisition rather than an exercise-and-sell or a gift. The warrants give the right to buy more shares later subject to the 4.99% ownership cap; they were part of the same purchase consideration.
Purchases by insiders can be interpreted as a vote of confidence but do not guarantee future performance. This filing is factual and does not state any intended use or sale of the warrants or shares.

Form 4

Period: 2026-05-29

Director

Transactions

Award
Class A Common Stock
[F1]
2026-05-29$1.96/sh+12,787$24,999→ 100,687 total
Award
Series A Warrant (right to buy)
[F1][F2]
2026-05-29+12,787→ 12,787 total
Exercise: $1.96From: 2026-11-29Exp: 2027-05-29→ Class A Common Stock (12,787 underlying)
Award
Series B Warrant (right to buy)
[F1][F2]
2026-05-29+12,787→ 12,787 total
Exercise: $2.34From: 2026-11-29Exp: 2031-05-29→ Class A Common Stock (12,787 underlying)

Footnotes (2)

[F1]On May 29, 2026, the Reporting Person purchased, in a registered direct offering, 12,787 shares of the Issuer's Class A Common Stock, as well as an accompanying Series A Warrant to purchase 12,787 shares of the Issuer's Class A Common Stock (or pre-funded warrants in lieu thereof) and an accompanying Series B Warrant to purchase 12,787 shares of the Issuer's Class A Common Stock (or pre-funded warrants in lieu thereof). The purchase price of each share of Issuer Class A Common Stock and accompanying Series A and Series B Warrant was $1.955. The issuance of such securities was approved by the Issuer's compensation committee of the board of directors in accordance with Rule 16(b)-3 of the Securities Exchange Act of 1934, as amended.
[F2]The Series A and Series B Warrants cannot be exercised for shares of the Issuer's Class A Common Stock if, as a result of such exercise, the holder, together with its affiliates and any other persons whose beneficial ownership would be aggregated for purposes of Section 13(d) of the Act, would beneficially own more than 4.99% of the total number of shares of the Issuer's Class A Common Stock then outstanding immediately following such exercise.

Signature

/s/ Sean M. Wirtjes, Attorney-in-Fact for Melinda Litherland Pei|2026-06-02

1 file