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Upstream Bio, Inc. (UPB) fair value: what the stock is really worth

As of Sep 23, 2026: fair value of Upstream Bio, Inc. $6.17, price $5.19, upside +18.9%, quality 31 out of 100. Calculated from audited financials with 26 valuation models and 37 quality factors, updated daily.

  1. Fair value above price? Yes
  2. Good quality? No
  3. Add to watchlist

Healthcare · US · ISIN US91678A1079

UB Upstream Bio, Inc. logo Thin data Sep 23, 2026

Upstream Bio, Inc.

UPB · US

SpeculativeUpside exists, but weak quality makes the signal speculative.

✓Fair value $6.17 · Undervalued (+19%)
!Quality 31/100
!Expensive Growth (revenue 3y +33.0 %/yr)
!negative free cash flow
!Trails peers (2/7)
!Narrow moat 8/100
!Evidence only low, so the estimate is less certain
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What runs behind every stock

26 valuation models 8 families, DCF to NCAV 37 quality factors margins, balance sheet, cashflow, debt 6 AI factors moat, what no ratio measures 2,000+ data points verified, per stock, median

69 individual criteria per stock, every one traceable See the method →

Price vs Fair Value

$32.60 $5.19 Fair Value $6.17 Oct 2024 Sep 2026

White line = price, green steps = our fair value per fiscal year, dashed = 300-day average. As of Sep 23, 2026.

How to read this chart

23‑month range $5.19 – $32.60 · fair‑value band $4.07 – $7.71 · the $5.19 price screens below the $6.17 fair value. Green steps = our fair value per fiscal year (point-in-time, no hindsight). Dashed = 300-day average. As of Sep 23, 2026.

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Company profile

Upstream Bio, Inc., a clinical-stage biotechnology company, develops treatments for inflammatory diseases focusing on severe respiratory disorders.

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Upstream Bio, Inc., a clinical-stage biotechnology company, develops treatments for inflammatory diseases focusing on severe respiratory disorders. It offers verekitug, which is in Phase 2 trials for the treatment of severe asthma and chronic rhinosinusitis with nasal polyps and chronic obstructive pulmonary disease and in Phase I clinical trial for treating chronic obstructive pulmonary disease. The company was incorporated in 2021 and is headquartered in Waltham, Massachusetts.

Stock analysis

Upstream Bio, Inc. (UPB) currently trades at $5.19, while our model-based Fair Value estimate is $6.17, implying the stock looks roughly 15.9% undervalued today.

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Valuation

How firm this estimate is: it rests on 1 models at a data quality of 92/100, which puts the evidence level at low.

Scenario range: $4.07 (bear) to $7.71 (bull), the price of $5.19 sits inside it. Bear and bull are the same models on cautious and optimistic assumptions, a range, not a price target.

Quality & growth

The Quality Score stands at 31/100 (below-average quality), in the Healthcare sector.

Expensive Growth: The company is growing, but growth may require heavy reinvestment or weak cash conversion.

Upstream Bio, Inc. reported revenue of $2.9M in FY2025 versus $1.2M in FY2022, a compound +33.0%/yr. Reported net income was −$143M in FY2025.

Key figures

Market cap $283M · P/S ratio 92.6 · EPS (TTM) $−2.88 · Return on equity −46.1% · Return on assets (EBIT) −56.3% · Operating margin −5,481% · Revenue (TTM) $3.2M · Revenue growth (YoY) −17.5%.

Competitive moat

Our AI-assisted moat analysis scores the competitive advantage at 32 out of 100 (low confidence).

What moves the price

The share trades about 84% below its 52-week high and at its 52-week low, currently below its 200-day average.

For context, the median of 10 Healthcare peers we cover trades at −5% fair-value upside, at 19%, UPB screens cheaper than that median.

Fair Value models

Bear $4.07 Fair Value $6.17 Bull $7.71
Model ⓘEach model values the company its own way (discounted cash flow, earnings, assets, dividends). The fair value above is their evidence-weighted blend, not the output of a single model. Bear ⓘBear = the cautious scenario: the same model computed with conservative anchors (lower growth, margins and valuation multiples). Together with Bull it frames a plausible valuation range, not a price target.BaseBull ⓘBull = the optimistic scenario: the same model computed with favourable anchors (higher growth, margins and valuation multiples). Together with Bear it frames a plausible valuation range, not a price target. Evidence ⓘEvidence = how well-backed THIS model's estimate is for this stock (0–100): how complete and reliable its input data are, and how well the model fits the company. The final Fair Value is an evidence-weighted blend, so better-evidenced models count more. Green ≥70, amber 50–69, grey below 50.
Highest evidence
NCAV (Graham) $3.10 $4.16 $6.20 51
All 1 models by family
Asset-Based
NCAV (Graham) $3.10 $4.16 $6.20 51

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Quality Score breakdown

Overall quality 31/100

Of which business quality 36 · Market factors (momentum, volatility) 4

Profitability 0
Margins and returns on capital today
Quality Growth 37
Are margins and returns improving?
Cashflow 10
Earnings quality: real cash, not paper profit
Fin. Strength 99
Balance sheet, leverage, solvency risk
Investment 40
Disciplined investing over empire-building
Low Volatility 0
Calm price path (market factor)
Momentum 9
Price trend over the last 3–12 months (market factor)
52W Momentum 0
Distance to the 52-week high (market factor)
Net Issuance 33
Share count: buybacks or dilution?

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Revenue & earnings trend

Growth Quality ⓘGrowth is valuable only when reinvestment earns attractive returns (Aswath Damodaran): sustainable growth depends on return on capital, reinvestment and efficiency. Basis: total company revenue over the periods shown on the cards (3Y/5Y/all years), not per share, so a merger can show up as a growth jump; per-share earnings growth is in the value-creation card. 44/100
The company is growing, but growth may require heavy reinvestment or weak cash conversion.
Revenue growth 1 year
+20.4%
Revenue growth 3 years ⓘMeasures the company's TOTAL revenue from reported annual statements: compound average growth per year (CAGR) from the fiscal year 3, 5 or N years back to the most recent comparable fiscal year. Not per share: buybacks do not change this number, and a merger can appear as a growth jump. Per-share growth (which does include buybacks) is in the value-creation card.
+33.0%
Profit margin (trend) ⓘOperating margin then vs now, from reported annual statements. A falling margin after a boom year is the classic peak-earnings signal: the growth rate then leans on an inflated base.
−1,972.7% (2022) → −5,618.8% (2025)
What shareholders gained per year ⓘWe only publish this rate when it is defensible. Reason: fiscal 2025 is a loss year, no rate is defined from a loss
not computed

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Peer GroupⓘHow this stock ranks against its industry: the green marker is this stock, the band is the typical 25–75% peer range, and the tick is the median.Biotechnology · 649 stocks

Beats the industry median on 2/6 measures
Overall it trails its industry peers.
Valuation
Quality Score 36 · Below median
Fair Value upside +19% · Top 25%
Profitability
Return on assets −30% · Bottom 25%
Growth and dividend
Revenue growth −18% · Bottom 25%

Valuation Multiplesvs Biotechnology median · lower = cheaper

P/B 0.83× · Cheaper than median
P/S (TTM) 89.68× · Priciest 25%

Strength profile in five axes (Snowflake)

VALUEFUTUREPASTHEALTHDIVIDEND
This stock
VALUEFUTUREPASTHEALTHDIVIDEND
Sector peers
VALUE (fair-value potential)59 · sector 0
FUTURE (revenue growth)0 · sector 0
PAST (return on equity)0 · sector 0
HEALTH (low debt)0 · sector 97
DIVIDEND (yield)0 · sector 23

Context: sector, industry, market

Values & ESG

Does this company touch areas you may want to avoid? The classification is inferred from sector and industry.

None of the checked exposures detected

Similar stocks

10 more Biotechnology stocks, each showing price versus our Fair Value estimate.

Stock Price Fair Value vs Fair Value
Vertex Pharmaceuticals Incorporated VRTX $516.34 $567.97 +10%
Regeneron Pharmaceuticals, Inc REGN $801.82 $1,252 +56%
argenx SE ARGX $963.79 $918.60 −5%
Samsung Biologics Co 207940 1,366,000 KRW 1,502,600 KRW +10%
CSL Limited CSL A$179.12 A$197.03 +10%
Alnylam Pharmaceuticals, Inc ALNY $251.65 $218.36 −13%
Royalty Pharma plc RPRX $58.52 $24.22 −59%
BeOne Medicines AG 6160 HK$218.20 HK$169.72 −22%
Celltrion, Inc 068270 177,400 KRW 74,519 KRW −58%
BioNTech SE BNTX $100.87 $63.62 −37%

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Upstream Bio, Inc. · Fair Value
$6.17 +16%Fair Value
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Cite: Fair Value Calculator (2026). "Upstream Bio, Inc. Fair Value". https://www.fairvalue-calculator.com/stock/UPB

Frequently asked questions

Is Upstream Bio, Inc. (UPB) overvalued or undervalued?
As of Sep 23, 2026, our model estimates a fair value of $6.17 versus a price of $5.19, about +19% upside (undervalued).
What is the fair value of UPB?
Our model-based fair value for Upstream Bio, Inc. is $6.17 (as of Sep 23, 2026), built from audited fundamentals. The current price: $5.19.
What is the quality score of UPB?
Upstream Bio, Inc. has a Quality Score of 31/100. It measures business quality (profitability, growth, cash flow, balance-sheet strength, investment discipline, share issuance). Market factors such as price momentum and volatility do not enter the number; they are shown separately in the detail view.
What is the price target for Upstream Bio, Inc. (UPB)?
Our model-based price target is the fair value of $6.17 (as of Sep 23, 2026) from 1 valuation models. Cautious scenario $4.07, optimistic scenario $7.71. It is a calculation from audited fundamentals, not an analyst target.
What is the Upstream Bio, Inc. stock forecast for 2026?
Our models put fair value at $6.17, about +19% upside versus a price of $5.19 (undervalued). Cautious scenario $4.07, optimistic scenario $7.71. The calculation is refreshed regularly with new filings.
What is the revenue of Upstream Bio, Inc. (UPB)?
Upstream Bio, Inc. reported trailing-twelve-month revenue of about $3.2M (latest available figure, as of Sep 23, 2026).
What is the intrinsic value of Upstream Bio, Inc. (UPB)?
Intrinsic value and fair value mean the same thing: what the business is worth on its numbers, independent of the share price. For Upstream Bio, Inc. it is $6.17 per share (as of Sep 23, 2026), against a price of $5.19. It is the blended result of 1 valuation models (cash flow, earnings, asset, dividend).
Is Upstream Bio, Inc. stock overvalued or undervalued in 2026?
As of Sep 23, 2026, UPB trades below its calculated fair value: price $5.19, fair value $6.17, a gap of about +19% (undervalued). The calculation is refreshed with each new quarterly report, so the verdict can change during the year.
Is fair value the same as the market price of UPB?
No. The price is what the market pays today ($5.19); the fair value is what the company's own numbers justify ($6.17). For Upstream Bio, Inc. the two are $0.9800 per share apart. That gap is exactly why we show both numbers side by side.
How much is Upstream Bio, Inc. worth?
The market values Upstream Bio, Inc. at about $283M (market capitalisation, as of Sep 23, 2026). Per share that is $5.19; our models calculate a fair value of $6.17 per share.
What do the bullish and bearish scenarios say about UPB?
Our models span a range for Upstream Bio, Inc.: cautious scenario $4.07, base $6.17, optimistic $7.71 per share (as of Sep 23, 2026, price $5.19). The range comes from different growth and margin assumptions, not from analyst opinions.
How solid is the balance sheet of Upstream Bio, Inc. (UPB)?
Balance-sheet figures for Upstream Bio, Inc. (as of Sep 23, 2026): return on equity −46.1%. They feed the Quality Score of 31/100, which measures business quality independently of the share price.
How far is UPB from its 52-week high?
Upstream Bio, Inc. trades at $5.19, about 84% below its 52-week high of $32.60 and at the low of $5.19 (as of Sep 23, 2026). Distance from the high says nothing about value: that is what the fair value of $6.17 is for.
Which stocks are comparable to Upstream Bio, Inc.?
From the same area (Healthcare) we also value Vertex Pharmaceuticals Incorporated, Regeneron Pharmaceuticals, Inc, argenx SE, Samsung Biologics Co, among others. Each of them has its own fair-value calculation on this site using the same models, so the comparison is like for like.
Is Upstream Bio, Inc. stock attractive at the current price?
The data as of Sep 23, 2026: price $5.19, calculated fair value $6.17 (+19%), Quality Score 31/100, from 1 models. Whether that fits your horizon and risk tolerance is your call. We provide the calculation, not investment advice.
How is the fair value of UPB calculated?
We run Upstream Bio, Inc. through 1 models from four families: discounted cash flow, earnings models, asset and balance-sheet models, and dividend models. Every model gets the same audited fundamentals; the result is the weighted average of $6.17, with the spread shown as a cautious and an optimistic scenario.
Is it still worth investing in stocks now?
The global stock market currently sits 13.0 % above its aggregate fair value. Upstream Bio, Inc. currently trades 19 % below its own fair value, and the market average says nothing about that. An expensive market is no reason to stay out and no reason to buy everything at once: keep a broad savings plan running, buy single stocks only with money you can do without, and hold part of your money liquid while the market is high. The full picture including sectors is on is it worth investing now.
What is the share price of Upstream Bio, Inc. (UPB)?
The closing price on Sep 23, 2026 was $5.19. Our model-based fair value is $6.17, about +19% upside (undervalued). We carry closing prices from our data provider, not a live tick.
What should I pay attention to with Upstream Bio, Inc. right now?
A fairly wide model range ($4.07 to $7.71) leaves room in how you read the outcome. Evidence is limited here (fewer models, shorter history), so the fair value is a rougher estimate than usual.

Key figures of Upstream Bio, Inc.

How large is the market capitalisation of Upstream Bio, Inc. (UPB)?
The market capitalisation of Upstream Bio, Inc. is $283M. The stock-market value of the whole company: share price times number of shares. It is what the market asks for the entire business today.
What is the P/S ratio of Upstream Bio, Inc. (UPB)?
The price-to-sales ratio of Upstream Bio, Inc. is 92.6 (last twelve months). Price to sales: market value relative to yearly revenue. Useful when profit is thin or distorted.
What are the earnings per share of Upstream Bio, Inc. (UPB)?
Earnings per share at Upstream Bio, Inc. are $−2.88. Earnings per share over the last twelve months: total profit spread across every single share.
What is the return on equity of Upstream Bio, Inc. (UPB)?
The return on equity (ROE) of Upstream Bio, Inc. is −46.1% (last twelve months). Profit relative to shareholders' equity, how efficiently the company works with its owners' money.
What is the EBIT return on assets of Upstream Bio, Inc. (UPB)?
On an EBIT basis the return on assets of Upstream Bio, Inc. is −56.3% (avg 4y). Operating profit (EBIT) relative to everything the company owns, as a multi-year average. It describes the business model rather than one good or bad year.
What is the operating margin of Upstream Bio, Inc. (UPB)?
The operating margin of Upstream Bio, Inc. is −5,481% (last twelve months). Profit from the core business (before interest and taxes) relative to revenue.
How fast is revenue growing at Upstream Bio, Inc. (UPB)?
Revenue at Upstream Bio, Inc. is growing −17.5% versus a year earlier (3y avg +33.0%). How much revenue grew versus a year earlier (YoY). The 3-year average next to it puts the single year in context.
How much free cash flow does Upstream Bio, Inc. (UPB) generate?
The free cash flow of Upstream Bio, Inc. is −$133M (fiscal year 2025). The cash truly left after running and investing in the business, this is what pays dividends and buybacks.
How much net cash does Upstream Bio, Inc. (UPB) hold?
Upstream Bio, Inc. holds more cash than debt, $100M net (fiscal year 2025). The company holds more cash than debt, a safety cushion.
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