Boundless Bio, Inc.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds.

(a)

Recent Sales of Unregistered Securities.

None.

(b)

Use of Proceeds.

On March 27, 2024, our registration statement on Form S-1 (File No. 333-277696), as amended, was declared effective by the SEC for our IPO. At the closing of the IPO on April 2, 2024, we sold 6,250,000 shares of common stock at a public offering price of $16.00 per share and received gross proceeds of $100.0 million, which resulted in net proceeds to us of approximately $87.7 million, after deducting underwriting discounts and commissions and other offering expenses.

The net proceeds from our IPO are held in cash, cash equivalents, or short-term investments pending the uses described below. As of March 31, 2026, we had used approximately $13.2 million of the net proceeds from our IPO to fund our operations, including our clinical development activities for BBI-940 and the KOMODO-1 trial and the wind down of the POTENTIATE trial. Our use of the net proceeds from our IPO, and our planned use of the remaining net proceeds, has changed from that described in the prospectus for our IPO due to our portfolio prioritization decisions, which have focused our activity on the BBI-940 program in lieu of other research programs and other ecDTx development programs, including the POTENTIATE and STARMAP trials. Net proceeds that may have been used to fund other research and development programs, and that are not used to wind down the POTENTIATE trial, have been, and are expected to be, used to support the development of BBI-940, including through initial proof-of-concept clinical data, and for working capital and other general corporate purposes. We may also use a portion of the net proceeds and our other cash, cash equivalents, and short-term investments to in-license, acquire, or invest in complementary businesses, technologies, products, or assets. However, we have no current commitments or obligations to do so. We cannot predict with certainty all of the particular uses for the net proceeds from our IPO. Our expected use of the net proceeds from our IPO represents our intentions based on our current plans and business conditions, which could change in the future as our plans and business conditions evolve. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress and costs of our clinical development activities, the status of and results from clinical trials and preclinical studies, as well as any collaborations that we may enter into with third parties for our ecDTx, the amount of cash used in our operations, and any unforeseen cash needs, as well as other factors described in Item 1A, “Risk Factors,” in our Annual Report on Form 10-K for the year ended December 31, 2025, as updated by our subsequent filings with the SEC. Our management has broad discretion in the application of the net proceeds from our IPO, and investors will be relying on their judgment regarding the application of the net proceeds.

(c)

Issuer Purchases of Equity Securities.

None.