Every Form 4 that Boundless Bio, Inc. (BOLD) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow BOLD and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full BOLD filings page.
Boundless Bio, Inc. (BOLD) had a significant shareholder group associated with Kevin Tang report the sale of 18,300 shares of Common Stock on 2026-08-26 at a weighted-average price of $2.97 per share, in transactions ranging from $2.90 to $3.03. Following this sale, entities affiliated with Tang Capital Partners beneficially hold 2,840,635 shares of Boundless Bio indirectly through several Tang Capital entities. The reporting persons stated they delivered to Boundless Bio the full disgorgeable profit of $10,046.70 arising from this sale and indicated that the transactions were not effected under a Rule 10b5-1 trading plan.
Boundless Bio, Inc. reported that investment entities managed by Tang Capital Management, associated with ten percent owner Kevin Tang, purchased a total of 4,863 shares of common stock in open market or private transactions at $2.44 per share between July 17 and July 21, 2026, through indirect ownership.
Tang Capital Management LLC and Kevin Tang, both reported as 10% owners of Boundless Bio, Inc., disclosed open‑market purchases of 63,969 shares of common stock on July 14–16, 2026 at weighted‑average prices between $2.41 and $2.44 per share.
After these transactions, Tang‑affiliated entities TCP, TCPI, TCP III and TCP IV beneficially own a combined 2,854,072 shares, including 654,055, 891,914, 654,048 and 654,055 shares respectively, in which Kevin Tang has a pecuniary interest through his roles with these entities.
Boundless Bio, Inc. ten percent owner entities associated with Kevin Tang reported open-market purchases of a total of 91,585 shares of Common Stock on July 9, 10 and 13, 2026, at weighted-average prices of $2.48, $2.43 and $2.42 per share, respectively. Following the latest transaction, investment vehicles managed by Tang Capital Management LLC, in which Kevin Tang has a pecuniary interest, beneficially own 2,790,103 shares of Boundless Bio common stock indirectly.
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, 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 director Nancy Whiting received a grant of stock options for 32,000 shares of Common Stock at an exercise price of $1.40 per share. The options vest in substantially equal monthly installments over 12 months after June 15, 2026, or in full at the next annual stockholder meeting before June 15, 2027, if earlier, contingent on continued board service.
Boundless Bio director Jonathan E. Lim received a grant of stock options for 48,000 shares of common stock. The options have an exercise price of $1.40 per share and expire on June 14, 2036.
The option grant vests in substantially equal monthly installments over the 12 months following June 15, 2026, or earlier in full on the date of the next annual stockholder meeting if that meeting occurs before June 15, 2027. Vesting is conditioned on Lim’s continued service on the board of directors.
Boundless Bio director James Christensen received a grant of stock options, giving him the right to buy 32,000 shares of Common Stock. The options have an exercise price of $1.4000 per share and expire on June 14, 2036.
The award vests in substantially equal monthly installments over the 12 months following June 15, 2026, or earlier on the date of the next annual stockholder meeting if that occurs before June 15, 2027, as long as he continues serving on the board of directors.
Boundless Bio, Inc. director Jennifer Lew received a grant of stock options covering 32,000 shares of common stock. The options have an exercise price of $1.4000 per share and expire on June 14, 2036. They vest in substantially equal monthly installments over the 12 months following June 15, 2026, or in full on the date of the next annual stockholder meeting if it occurs before June 15, 2027, subject to her continued board service. This is a compensation-related award and does not involve any open-market buying or selling of shares.
Boundless Bio, Inc. granted a stock option to Chief Legal Officer and Corporate Secretary Jessica Oien. The option covers 220,000 shares of common stock at an exercise price of $1.26 per share.
The option was awarded on January 23, 2026 and expires on January 22, 2036. Vesting starts on January 1, 2026 and occurs in 48 substantially equal monthly installments, so 1/48th of the option vests on February 1, 2026 and monthly thereafter, aligning the award with long-term service at the company.
Boundless Bio, Inc. granted Chief Scientific Officer Christian Hassig a stock option covering 230,000 shares of common stock on January 23, 2026. The option has an exercise price of $1.26 per share and was received at no cost on the grant date. It is held directly by the reporting person.
The vesting start date is January 1, 2026. The option vests in 48 substantially equal monthly installments, with 1/48 of the award vesting on February 1, 2026 and additional 1/48 portions vesting each month thereafter until fully vested.
Boundless Bio, Inc. Chief Medical Officer Robert Doebele reported receiving a stock option award on January 23, 2026. The option covers 230,000 shares of Boundless Bio common stock at an exercise price of $1.26 per share, held directly.
The vesting commencement date is January 1, 2026. The option vests in 48 substantially equal monthly installments, so 1/48th of the award vests on February 1, 2026 and then monthly thereafter until fully vested. Following this grant, Doebele beneficially owns 230,000 derivative securities in the form of stock options.
Boundless Bio, Inc. reported that its President and CEO, Zachary Hornby, received a grant of a stock option covering 600,000 shares of common stock. The option has an exercise price of $1.26 per share and was granted on January 23, 2026.
The option begins vesting from a commencement date of January 1, 2026, in 48 substantially equal monthly installments. As a result, 1/48th of the option vests on February 1, 2026, with additional monthly vesting thereafter until fully vested, and it is scheduled to expire on January 22, 2036.
Boundless Bio, Inc. reported that officer David A. Hinkle received a new stock option award. On January 23, 2026, he was granted an option to purchase 140,000 shares of common stock at an exercise price of $1.26 per share.
The option’s vesting start date is January 1, 2026. It vests in 48 substantially equal monthly installments, so 1/48 of the option vests on February 1, 2026 and then continues to vest monthly until fully vested on the fourth anniversary, assuming continued service.