Welcome to our dedicated page for Boundless Bio SEC filings (Ticker: BOLD), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Boundless Bio, Inc. filings document a clinical-stage oncology issuer focused on ecDNA-directed cancer therapeutics, with formal disclosures on operating results, research programs, and material events. Recent 8-K reports furnish quarterly and annual financial results and business updates for BBI-940, KOMODO-1, and the discontinued POTENTIATE program involving BBI-355 and BBI-825.
Its proxy and current reports also cover board composition, director elections, auditor ratification, stockholder voting results, and facility-related obligations, including lease-termination arrangements. These filings frame the company’s clinical-development disclosures, public-company governance, capital allocation, and operating obligations.
Boundless Bio, Inc. reported that entities associated with Tang Capital Partners made open-market purchases of a total of 57,210 shares of common stock over three days. The buys on July 6–8, 2026 were executed at weighted-average prices between $2.46 and $2.49 per share.
Following these transactions, the indirect holdings reported as "By LP" increased to 2,698,518 shares of Boundless Bio common stock. Footnotes state that various Tang Capital funds collectively beneficially own these shares and that Kevin Tang has a pecuniary interest in the positions.
Boundless Bio, Inc. reported insider activity involving entities affiliated with ARCH Venture funds and investment committee member Kristina Burow. On July 1, 2026, a cashless stock option exercise for 16,000 shares of common stock at $1.03 per share was completed, followed by an open-market sale of 16,000 shares at $2.49 per share, with net proceeds remitted to ARCH funds. The filing also shows indirect holdings of 1,181,766, 828,570 and 683,759 shares of common stock as of that date.
Boundless Bio, Inc. received a Form 4 from ARCH-affiliated entities detailing a cashless stock option exercise and same-day sale tied to director Kristina Burow’s compensation. A stock option for 16,000 shares of common stock was exercised at $1.03 per share and the resulting 16,000 shares were sold in an open-market transaction at $2.49 per share. According to the footnotes, the net proceeds from this exercise and sale were remitted to ARCH Venture Fund IX, L.P., ARCH Venture Fund IX Overage, L.P., and ARCH Venture Fund X Overage, L.P., which continue to report substantial indirect holdings of Boundless Bio common stock.
Boundless Bio, Inc. insider entities affiliated with Kevin Tang reported open-market purchases of a total of 107,463 shares of Common Stock at prices around $2.49–$2.60 per share over three days. The transactions were made indirectly through limited partnerships managed by Tang Capital Management, LLC.
Following these purchases, the reporting entities collectively beneficially own 2,641,308 shares of Boundless Bio Common Stock, as described in the filing’s ownership breakdown for Tang Capital Partners, LP and related entities. All reported trades were classified as open-market purchases, with no sales or derivative transactions disclosed.
Boundless Bio disclosed ownership by Tang-linked investors totaling 11.3%. The Schedule 13G states 2,533,845 shares are beneficially owned collectively by Tang Capital Management, Kevin Tang and affiliated entities, based on 22,474,777 shares outstanding as of June 15, 2026.
The filing lists shared voting and dispositive power across Tang Capital Management, Tang Capital Partners, Tang Capital Partners International, Tang Capital Partners III, Tang Capital Partners IV and Kevin Tang; signatures are dated June 29, 2026.
Boundless Bio, Inc. insider entities affiliated with Tang Capital reported multiple open-market purchases of Common Stock. Across June 25–29, 2026, they bought a net 286,333 shares at weighted-average prices generally between about $2.40 and $2.60 per share.
Individual trades ranged from 134 shares to 145,880 shares per transaction, with reported per-share prices such as $2.48, $2.47, $2.54, $2.55 and $2.56. The positions are held indirectly "By LP" through Tang Capital limited partnership vehicles.
According to the filing, Tang Capital-related entities beneficially own 580,669, 791,839, 580,668 and 580,669 shares in four affiliated vehicles, for an aggregate beneficial holding of 2,533,845 shares after these purchases. Kevin Tang has a pecuniary interest in these indirectly held shares.
Boundless Bio, Inc. insider filings show that entities affiliated with Tang Capital report initial beneficial ownership of the company’s common stock. The Form 3 indicates indirect holdings of 2,247,512 shares of common stock, held by limited partnership and corporate vehicles associated with Tang Capital.
Kevin Tang is described as the sole manager or director of these entities and has a pecuniary interest in the shares they beneficially own. The filing is an initial ownership report and does not show any new purchases or sales of Boundless Bio stock.
Boundless Bio (BOLD) agreed to merge with Serapha Bio under an Agreement and Plan of Merger dated June 22, 2026. On a pro forma, fully diluted basis, Serapha equityholders are expected to own approximately 96.31% of the combined company and pre‑Merger Boundless Bio equityholders approximately 3.69%. The transaction contemplates a Form S-4 filing, a reverse stock split and an increase in authorized shares, and is conditioned on stockholder approvals, Nasdaq listing approval and a $200 million minimum cash raise in Serapha’s Securities Purchase Agreement.
Concurrent financings include a Series A preferred financing of ~$138.0 million and a PIPE Pre-Closing Financing of ~$92.0 million. Boundless Bio announced a workforce reduction of approximately 75%, with estimated one‑time charges of $3.0 million to $5.0 million, largely to be recognized in Q3 2026. Management and board composition of the combined company will be determined by Serapha.
Boundless Bio agreed to an all-stock merger with private biotech Serapha Bio, creating a combined company focused on Serapha’s in vivo base-editing therapy SERP-01 for Alpha‑1 Antitrypsin Deficiency. Based on the merger exchange ratio, Serapha equityholders are expected to own about 96.3% of the combined company on a fully diluted basis, with Boundless Bio equityholders owning about 3.7%.
Before closing, Boundless Bio may declare a cash dividend to its pre‑merger stockholders, currently expected to total roughly $44–$48 million, reflecting excess net cash. Serapha has already raised approximately $138 million in Series A preferred financing and secured an additional $92 million PIPE commitment, giving the combined company expected cash runway into the second half of 2029.
In connection with the merger, Boundless Bio will cut about 75% of its workforce, incurring one‑time charges of approximately $3.0–$5.0 million, and will wind down its BBI‑940 oncology program after early clinical data showed human exposure below preclinical expectations. CEO Zachary Hornby and several senior R&D leaders will depart, with Chief Legal Officer Jessica Oien becoming principal executive officer during the transition. All outstanding employee stock options have been fully vested and their exercise period extended, while underwater Boundless Bio options with exercise prices above $8.00 will be cancelled at closing.
Boundless Bio, Inc. held its annual stockholder meeting on June 15, 2026, where two proposals were approved. Stockholders elected James Christensen, Ph.D. and Jennifer Lew as Class II directors to serve until the 2029 annual meeting and until their successors are elected and qualified.
Christensen received 9,287,096 votes for and 512,585 votes withheld, while Lew received 9,271,084 votes for and 528,597 votes withheld; each had 5,757,105 broker non-votes. Stockholders also ratified KPMG LLP as the independent registered public accounting firm for the fiscal year ending December 31, 2026, with 15,376,973 votes for, 127,747 against and 52,066 abstentions.