Upstream Bio, Inc.
NASDAQ: UPB · HEALTHCARE · BIOTECHNOLOGY
Updated 2026-04-29
Upstream Bio, Inc. (UPB) Stock Valuation Analysis
Fair value estimate, historical valuation range, and quality signals for UPB.
Current price exceeds what fundamentals support. Risk/reward skewed unfavorably.
UPB historical valuation range
Where current P/E sits in UPB's own 5Y range.
UPB intrinsic value (DCF)
DCF-based fair value estimate vs current market price.
Standard discounted cash flow models produce unreliable output for unprofitable or near-breakeven companies. Revenue-based multiples such as P/S and EV/Sales, combined with the historical valuation position above, give a more reliable read for this stock.
Intrinsic value calculated using discounted cash flow (DCF) model based on projected free cash flows, discount rate, and terminal growth assumptions. A positive margin of safety indicates the current price is below estimated fair value, providing a cushion against estimation error.
UPB valuation signals
Quick-read green flags, caution flags, and risks based on current metrics.
P/E Ratio — History
P/S Ratio — History
Current: 175.23x
Is UPB overvalued in 2026?
Upstream Bio, Inc. (UPB) currently trades at $9.19 per share with a market capitalization of $500,120,000.00. Based on our multi-factor framework, the stock appears richly valued with a Smart Value Score of 32/100. This score blends growth quality, financial health, and price attractiveness into a single institutional-grade read.
UPB currently has no meaningful P/E ratio, which typically signals that the company is unprofitable, near breakeven, or emerging from a loss-making period. With a P/S ratio of 175.2x, the market is valuing the company primarily on its revenue rather than its earnings.
A standard DCF model does not produce reliable output for UPB under current conditions. For unprofitable or near-breakeven companies, revenue-based multiples such as EV/Sales and historical P/S percentile are more informative than intrinsic value calculations.
Financial quality is a concern. The Piotroski F-Score of 0/9 flags weakening fundamentals that deserve closer scrutiny before the valuation case can be fully trusted.
Bottom line: UPB appears richly valued on our framework, with a Smart Value Score of 32/100. At current levels the risk/reward is skewed against the buyer. A materially lower price or significant operational improvement would be needed to change the picture.
Frequently asked questions
Is UPB overvalued in 2026?
Based on a Smart Value Score of 32/100, UPB appears overvalued. Current price exceeds what fundamentals currently justify.
What is UPB's fair value?
Standard DCF is unreliable for UPB due to its current profitability profile. Revenue-based approaches such as EV/Sales or historical P/S percentile are more informative for this stock.
What P/E ratio does UPB trade at?
UPB does not have a meaningful P/E ratio at this time, typically a sign of unprofitability or an ongoing earnings transition.
Is UPB a buy based on valuation?
WallStSmart does not issue buy or sell recommendations. Our Smart Value Score of 32/100 reflects the combined read on growth, quality, and price. The profile skews cautious. Consider waiting for a better price or clearer operational improvement.
How does UPB's valuation compare to its history?
Insufficient historical valuation data exists yet for a confident percentile read on UPB.
What is UPB's Smart Value Score?
UPB's Smart Value Score is 32/100. The Smart Value Score is a proprietary WallStSmart metric blending growth quality, financial health, and valuation attractiveness into a single 0-100 read. Scores above 75 are rare and indicate strong multi-factor alignment.