Norges Bank Increases Stake in Upstream Bio Inc to 5.3%

Norges Bank has filed a Schedule 13G with the SEC, disclosing an increased ownership of 5.3% in Upstream Bio Inc. The filing indicates that Norges Bank now holds 2,882,647 shares of the company's common stock, representing a significant increase from previous holdings. The shares are held on behalf of the Government of Norway and were acquired in the ordinary course of business, not for the purpose of influencing the control of the issuer. The filing was signed by Aya Sobhy, Business and Regulatory Compliance, on October 24, 2025.