Rapid Micro Biosystems, Inc. has 5 Schedule 13D or 13G filings on record since 2025-08-19. 5 holders' latest filing reports 5% or more of class a common stock, par value $0.01 per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Bain Capital Life Sciences Fund, L.P. | 16.76% | 7,651,369 | SCHEDULE 13G/A, 2026-08-14 | 2026-06-30 |
| Longitude Capital Partners II, LLC | 8.6% | 3,529,245 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| Armistice Capital, LLC | 7.29% | 3,328,000 | SCHEDULE 13G, 2026-08-14 | 2026-06-30 |
| Spignesi Robert G Jr | 6.3% | 2,647,256 | SCHEDULE 13D, 2025-08-19 | 2024-03-28 |
| Endeavour Medtech Growth II LP | 5.7% | 2,257,099 | SCHEDULE 13G/A, 2026-02-13 | 2025-12-31 |
Purpose of Transaction (Item 4)
Spignesi Robert G Jr
The information set forth or incorporated by reference in Items 3 and 6 of this Statement is incorporated by reference into this Item 4. The Reporting Person intends to continuously review his investment in the Issuer and may in the future determine (1) to acquire additional securities of the Issuer, through open market purchases, private agreements or otherwise, (2) to dispose of all or a portion of the securities of the Issuer owned by him or (3) to take any other available course of action. Notwithstanding anything contained herein, the Reporting Person specifically reserves the right to change his intention with respect to any or all of such matters. In reaching any decision as to his course of action (as well as to the specific elements thereof), the Reporting Person currently expects that he would take into consideration a variety of factors, including, but not limited to, the following: the Issuer's business and prospects; other developments concerning the Issuer and its business generally; other business opportunities available to the Reporting Person; developments with respect to the business of the Reporting Person; changes in law and government regulations; general economic conditions; and money and stock market conditions, including the market price of the securities of the Issuer. The Reporting Person is President and Chief Executive Officer and a member of the Board of Directors of the Issuer and, accordingly, in such capacity, may have influence over the …The first part of Item 4 of the SCHEDULE 13D filed 2025-08-19; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-19 | Spignesi Robert G Jr | 6.3% | SCHEDULE 13D |
| 2026-02-13 | Endeavour Medtech Growth II LP | 5.7% | SCHEDULE 13G/A |
| 2026-05-15 | Longitude Capital Partners II, LLC | 8.6% | SCHEDULE 13G/A |
| 2026-08-14 | Armistice Capital, LLC | 7.29% | SCHEDULE 13G |
| 2026-08-14 | Bain Capital Life Sciences Fund, L.P. | 16.76% | SCHEDULE 13G/A |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.