Form 4 Filing for Boundless Bio, Inc.

This filing details non-derivative transactions by TANG CAPITAL MANAGEMENT LLC and TANG KEVIN, both 10% owners of Boundless Bio, Inc. (BOLD). On July 14, 2026, 43,878 shares of Common Stock were acquired at a weighted-average price of $2.43, with prices ranging from $2.41 to $2.44. On July 15, 2026, 1,600 shares were acquired at $2.44. On July 16, 2026, 18,491 shares were acquired at $2.44. Following these transactions, the post-transaction share count for the reporting persons is 2,854,072. These transactions were executed under Form 4 filing type. Footnote 2 provides details on the complex beneficial ownership structure involving various Tang Capital entities.