Bambusa Therapeutics fund investor buys 2.34M shares
The October 30 purchase prices fell within disclosed ranges of $13.61–$14.58 and $14.65–$15.00 per share.
Sentiment and the balance of points
Rhea-AI Sentiment reads the wording of the document, how positive or negative its language is on a 1 to 5 scale. The balance of points shown with the takes weighs what the document actually discloses, so the two can disagree, for example when a trial that missed its main goal is described in upbeat language.
Form Type
4
Rhea-AI Filing Summary
Bambusa Therapeutics, Inc. (BBTX) had common-stock purchases by RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund III, L.P. On October 30, 2026, the Fund purchased 189,909 shares at a $14.23 weighted-average price, while Nexus Fund III purchased 263,911 shares at a $14.92 weighted-average price. On November 2, 2026, the Fund bought 2,335,109 shares and Nexus Fund III bought 164,891 shares, each at $16 per share. Preferred shares held by the funds automatically converted one-for-one into common stock before the initial public offering closed; the conversion entries show 3,144,858 common shares for the Fund and 1,331,080 for Nexus Fund III.
Insider Trade Summary
Net Buyer: 2,953,820 shares
Net Buy
10 txns
Insider
RA CAPITAL MANAGEMENT, L.P., RA Capital Healthcare Fund LP, RA Capital Nexus Fund III, L.P., Kolchinsky Peter, Shah Rajeev M.
Role
Director, 10% Owner | Director, 10% Owner | Director | Director, 10% Owner | Director, 10% Owner
Bought
2,953,820 shs ($46.64M)
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Conversion | Series A-1 Preferred Stock F5, F2, F3 | 2,844,910 | $0.00 | $0.00 |
| Conversion | Series A-1 Preferred Stock F5, F2, F6 | 1,278,148 | $0.00 | $0.00 |
| Conversion | Series A-2 Preferred Stock F5, F2, F3 | 299,948 | $0.00 | $0.00 |
| Conversion | Series A-2 Preferred Stock F5, F2, F6 | 52,932 | $0.00 | $0.00 |
| Conversion | Common Stock F5, F2, F3 | 3,144,858 | -- | -- |
| Conversion | Common Stock F5, F2, F6 | 1,331,080 | -- | -- |
| Purchase | Common Stock F2, F3 | 2,335,109 | $16.00 | $37.36M |
| Purchase | Common Stock F2, F6 | 164,891 | $16.00 | $2.64M |
| Purchase | Common Stock F1, F2, F3 | 189,909 | $14.23 | $2.70M |
| Purchase | Common Stock F4, F2, F3 | 263,911 | $14.92 | $3.94M |
Holdings After Transaction:
Series A-1 Preferred Stock — 0 contracts (Indirect, See footnotes);
Series A-2 Preferred Stock — 0 contracts (Indirect, See footnotes);
Common Stock — 1,495,971 shares (Indirect, See footnotes)
Footnotes (6)
- F1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $13.61 to $14.58 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.
- F2. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund") and RA Capital Nexus Fund III, L.P. (the "Nexus Fund III"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.
- F3. Held directly by the Fund.
- F4. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $14.65 to $15.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.
- F5. All shares of the preferred stock, par value $0.00001 per share, of the Issuer automatically converted on a one-for-one basis to shares of the Issuer's common stock, par value $0.00001 per share ("Common Stock") prior to the closing of the Issuer's initial public offering of its Common Stock.
- F6. Held directly by the Nexus Fund III.
Key Figures
Common-stock purchase: 189,909 shares at a $14.23 weighted-average price
Common-stock purchase: 263,911 shares at a $14.92 weighted-average price
Common-stock purchase: 2,335,109 shares at $16 per share
+3 more
6 metrics
Common-stock purchase
189,909 shares at a $14.23 weighted-average price
RA Capital Healthcare Fund, L.P.; October 30, 2026
Common-stock purchase
263,911 shares at a $14.92 weighted-average price
RA Capital Nexus Fund III, L.P.; October 30, 2026
Common-stock purchase
2,335,109 shares at $16 per share
RA Capital Healthcare Fund, L.P.; November 2, 2026
Common-stock purchase
164,891 shares at $16 per share
RA Capital Nexus Fund III, L.P.; November 2, 2026
Common shares from preferred-stock conversion
3,144,858 shares
RA Capital Healthcare Fund, L.P.; one-for-one conversion before the initial public offering closed
Common shares from preferred-stock conversion
1,331,080 shares
RA Capital Nexus Fund III, L.P.; one-for-one conversion before the initial public offering closed
Key Terms
weighted average price, initial public offering, beneficial ownership, pecuniary interest
4 terms
weighted average price financial
"The price reported in Column 4 is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
initial public offering financial
"prior to the closing of the Issuer's initial public offering"
An initial public offering (IPO) is when a private company first sells its shares to the public and becomes a stock-listed company. It matters because it allows the company to raise money from a wide range of investors, helping it grow, while giving early shareholders a way to sell some of their ownership.
beneficial ownership regulatory
"disclaims beneficial ownership of any of the reported securities"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
pecuniary interest regulatory
"except to the extent of its or his respective pecuniary interest therein"
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