Rapid Micro Biosystems' (RPID) finance chief, Sean M. Wirtjes, completed an internal share sale on March 11, 2026, disposing of 7,480 Class A common shares at a single price of $4.3181 each. The transaction generated approximately $32,299 and, according to the required Form 4 filed with the Securities and Exchange Commission, was executed at one price point.
Following the sale, Wirtjes retains direct ownership of 556,194 Rapid Micro Biosystems shares. The filing specifies that the sale was an automatic disposition intended to satisfy the tax liability associated with the vesting of restricted stock units.
The trade took place above the company’s most recent market quote. The stock is currently trading at $3.42 and has fallen nearly 17% over the past week, reflecting recent short-term volatility in the share price.
Alongside the insider transaction, the company reported its Q4 2025 financial results, which showed revenue of $11.3 million. That revenue figure exceeded the consensus forecast of $9.83 million and represented a 37% increase compared with the same quarter a year earlier. Despite the top-line beat, the company posted a net loss per share of $0.28, which was wider than the expected loss of $0.225 per share.
The combination of an insider sale to meet tax obligations and recent financial results provides investors with discrete datapoints about executive liquidity moves and company performance. The sale itself was described as routine and tied to tax withholding rather than a discretionary cash-raising event, according to the disclosures in the Form 4.
Investors and market participants have reacted to the recent earnings and subsequent price action, leaving the stock trading below the price at which the CFO’s shares were sold. The filings and quarterly figures form the current public record of the transaction and the company’s recent operating results.
Summary
Rapid Micro Biosystems CFO Sean M. Wirtjes sold 7,480 shares on March 11, 2026, at $4.3181 per share to cover taxes related to vested restricted stock units, netting about $32,299. He now directly owns 556,194 shares. The company reported Q4 2025 revenue of $11.3 million, beating the $9.83 million forecast and rising 37% year-over-year, while reporting a net loss per share of $0.28 versus an expected -$0.225. The share price has declined to $3.42, down nearly 17% over the past week.
Key points
- Insider transaction - CFO sold 7,480 Class A shares at $4.3181 each on March 11, 2026, for approximately $32,299; the sale was executed at a single price point and reported on a Form 4.
- Post-sale holdings - Sean M. Wirtjes directly holds 556,194 Rapid Micro Biosystems shares following the automatic sale to cover tax obligations associated with vested RSUs.
- Company performance - Rapid Micro Biosystems recorded Q4 2025 revenue of $11.3 million, topping the $9.83 million forecast and rising 37% year-over-year, while reporting a larger-than-expected net loss per share of $0.28.
Risks and uncertainties
- Share-price volatility - The company’s stock has fallen to $3.42 and declined nearly 17% over the prior week, indicating short-term market volatility that could affect equity holders and trading liquidity.
- Earnings shortfall - Despite a revenue beat, the magnitude of the net loss per share exceeded expectations, creating uncertainty about near-term profitability trends and investor sentiment.
- Limited disclosure on motives beyond tax withholding - The Form 4 describes the sale as automatic to satisfy tax obligations on vested RSUs; no additional information was provided about other potential reasons for the disposition.