Why did UPB's operating expenses surge in Q4 2024?

The surge in operating expenses for Upstream Bio Inc. (UPB) in Q4 2024 can be attributed to several factors:

1. **Expansion of Operations**: UPB expanded its warehouse and operations team to support growth, which led to increased lease expenses, employee salary and benefits, and temporary labor costs. This expansion likely required additional space, resulting in higher lease expenses and utilities.
2. **Increased Freight Expenses**: The company's transportation services revenue increased due to the addition of new warehouse locations, which enabled an increase in shipment volume compared to the same period in 2023. This increase in freight volume would have led to higher freight expenses.

In summary, the surge in operating expenses was likely driven by the company's expansion of operations and increased freight expenses associated with growth.