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Rallybio Corp (RLYB) fair value: what the stock is really worth

As of Sep 23, 2026: fair value of Rallybio Corp $10.72, price $16.86, upside -36.4%, quality 60 out of 100. Calculated from audited financials with 26 valuation models and 37 quality factors, updated daily.

  1. Fair value above price? No
  2. Good quality? Yes
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Healthcare · US · ISIN US75120L2097

RC Rallybio Corp logo Thin data Sep 23, 2026

Rallybio Corp

RLYB · US

Stretched ValuationStrong overvaluation with only moderate quality.

!Fair value $10.72 · Strongly overvalued (−36%)
!Quality 60/100
!Mixed Growth (revenue YoY +34.9 %/yr)
!negative free cash flow
✓Ranks above peers (5/7)
!Moderate moat 49/100
!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

$187.20 $2.00 Fair Value $10.72 Jul 2021 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

60‑month range $2.00 – $187.20 · fair‑value band $7.07 – $13.40 · the $16.86 price screens above the $10.72 fair value. Dashed = 300-day average. As of Sep 23, 2026.

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Company profile

Rallybio Corporation, a clinical-stage biotechnology company, engages in the development and commercialization of life-transforming therapies for patients suffering from severe and rare diseases.

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Rallybio Corporation, a clinical-stage biotechnology company, engages in the development and commercialization of life-transforming therapies for patients suffering from severe and rare diseases. Its lead product candidate is the RLYB116, an inhibitor of complement component 5 (C5) to treat several diseases of complement dysregulation which has completed phase 1 trial; and RLYB332, a preclinical antibody, for the treatment of severe anemia with ineffective erythropoiesis and iron overload. The company has a strategic alliance with AbCellera to discover, develop, and commercialize novel antibody-based therapeutics for rare diseases, as well as collaboration agreement with Johnson & Johnson to provide therapeutic solutions for pregnant individuals at risk of fetal and neonatal alloimmune thrombocytopenia. Rallybio Corporation was founded in 2018 and is headquartered in New Haven, Connecticut.

Stock analysis

Rallybio Corp (RLYB) currently trades at $16.86, while our model-based Fair Value estimate is $10.72, implying the stock looks roughly 57.3% overvalued today.

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Valuation

How firm this estimate is: it rests on 1 models at a data quality of 96/100, which puts the evidence level at low.

Scenario range: $7.07 (bear) to $13.40 (bull), the price of $16.86 sits above 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 60/100 (solid quality), in the Healthcare sector.

Mixed Growth: Revenue is growing, but margins or cash flow do not fully confirm the trend.

Rallybio Corp reported revenue of $858K in FY2025 versus $0 in FY2021. Reported net income was −$9.0M in FY2025.

Key figures

Market cap $97.8M · P/E ratio 2.1 · EPS (TTM) $7.99 · Net margin 7,051% · Return on equity 64.9% · Return on assets (EBIT) −53.0% · Operating margin −3,935% · Revenue (TTM) $646K.

Competitive moat

Our AI-assisted moat analysis scores the competitive advantage at 28 out of 100 (low confidence).

What moves the price

The share trades about 2% below its 52-week high and 322% above its 52-week low, currently above its 200-day average.

For context, the median of 10 Healthcare peers we cover trades at −5% fair-value upside, at −36%, RLYB screens richer than that median.

Fair Value models

Bear $7.07 Fair Value $10.72 Bull $13.40
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. Based on fiscal year 2025 figures (about 9 months old). Earnings retained since then ($5.87 per share) are deliberately not added. 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) $5.45 $7.31 $10.91 51
All 1 models by family
Asset-Based
NCAV (Graham) $5.45 $7.31 $10.91 51

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Quality Score breakdown

Overall quality 60/100

Of which business quality 57 · Market factors (momentum, volatility) 79

Profitability 0
Margins and returns on capital today
Quality Growth 70
Are margins and returns improving?
Cashflow 50
Earnings quality: real cash, not paper profit
Fin. Strength 100
Balance sheet, leverage, solvency risk
Investment 100
Disciplined investing over empire-building
Low Volatility 50
Calm price path (market factor)
Momentum 86
Price trend over the last 3–12 months (market factor)
52W Momentum 99
Distance to the 52-week high (market factor)
Net Issuance 42
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. 51/100
Revenue is growing, but margins or cash flow do not fully confirm the trend.
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

RLYB screens 57% overvalued. Compare with Vertex Pharmaceuticals Incorporated →

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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 5/7 measures
Overall it ranks above its industry peers.
Valuation
Quality Score 57 · Top 25%
Fair Value upside −36% · Above median
Profitability
Return on equity (TTM) 65% · Top 25%
Return on assets −21% · Below median
Growth and dividend
Revenue growth 0% · Above median

Valuation Multiplesvs Biotechnology median · lower = cheaper

P/E (TTM) 2.1× · Cheapest 25%
P/B 1.69× · Pricier than median

Strength profile in five axes (Snowflake)

VALUEFUTUREPASTHEALTHDIVIDEND
This stock
VALUEFUTUREPASTHEALTHDIVIDEND
Sector peers
VALUE (fair-value potential)0 · sector 0
FUTURE (revenue growth)0 · sector 0
PAST (return on equity)100 · sector 0
HEALTH (low debt)0 · sector 97
DIVIDEND (yield)0 · sector 23

VALUE 0: the price sits above our fair-value range.

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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Rallybio Corp · Fair Value
$10.72 −57%Fair Value
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Cite: Fair Value Calculator (2026). "Rallybio Corp Fair Value". https://www.fairvalue-calculator.com/stock/RLYB

Frequently asked questions

Is Rallybio Corp (RLYB) overvalued or undervalued?
As of Sep 23, 2026, our model estimates a fair value of $10.72 versus a price of $16.86, about −36% upside (overvalued).
What is the fair value of RLYB?
Our model-based fair value for Rallybio Corp is $10.72 (as of Sep 23, 2026), built from audited fundamentals. The current price: $16.86.
What is the quality score of RLYB?
Rallybio Corp has a Quality Score of 60/100. 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 Rallybio Corp (RLYB)?
Our model-based price target is the fair value of $10.72 (as of Sep 23, 2026) from 1 valuation models. Cautious scenario $7.07, optimistic scenario $13.40. It is a calculation from audited fundamentals, not an analyst target.
What is the Rallybio Corp stock forecast for 2026?
Our models put fair value at $10.72, about −36% upside versus a price of $16.86 (overvalued). Cautious scenario $7.07, optimistic scenario $13.40. The calculation is refreshed regularly with new filings.
What is the revenue of Rallybio Corp (RLYB)?
Rallybio Corp reported trailing-twelve-month revenue of about $646K (latest available figure, as of Sep 23, 2026).
What is the intrinsic value of Rallybio Corp (RLYB)?
Intrinsic value and fair value mean the same thing: what the business is worth on its numbers, independent of the share price. For Rallybio Corp it is $10.72 per share (as of Sep 23, 2026), against a price of $16.86. It is the blended result of 1 valuation models (cash flow, earnings, asset, dividend).
Is Rallybio Corp stock overvalued or undervalued in 2026?
As of Sep 23, 2026, RLYB trades above its calculated fair value: price $16.86, fair value $10.72, a gap of about −36% (overvalued). 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 RLYB?
No. The price is what the market pays today ($16.86); the fair value is what the company's own numbers justify ($10.72). For Rallybio Corp the two are $6.14 per share apart. That gap is exactly why we show both numbers side by side.
How much is Rallybio Corp worth?
The market values Rallybio Corp at about $97.8M (market capitalisation, as of Sep 23, 2026). Per share that is $16.86; our models calculate a fair value of $10.72 per share.
What do the bullish and bearish scenarios say about RLYB?
Our models span a range for Rallybio Corp: cautious scenario $7.07, base $10.72, optimistic $13.40 per share (as of Sep 23, 2026, price $16.86). The range comes from different growth and margin assumptions, not from analyst opinions.
What is the P/E ratio of RLYB?
Rallybio Corp trades at a price-to-earnings ratio of 2.1 (as of Sep 23, 2026). A P/E on its own says little: it compares the price with ONE year of profit, while our fair value of $10.72 is built from several models across several years. Other multiples: P/B 1.7.
How solid is the balance sheet of Rallybio Corp (RLYB)?
Balance-sheet figures for Rallybio Corp (as of Sep 23, 2026): return on equity 64.9%. They feed the Quality Score of 60/100, which measures business quality independently of the share price.
How far is RLYB from its 52-week high?
Rallybio Corp trades at $16.86, about 2% below its 52-week high of $17.22 and 322% above the low of $3.99 (as of Sep 23, 2026). Distance from the high says nothing about value: that is what the fair value of $10.72 is for.
Which stocks are comparable to Rallybio Corp?
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 Rallybio Corp stock attractive at the current price?
The data as of Sep 23, 2026: price $16.86, calculated fair value $10.72 (−36%), Quality Score 60/100, 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 RLYB calculated?
We run Rallybio Corp 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 $10.72, 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. Rallybio Corp itself currently trades above fair value. 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 Rallybio Corp (RLYB)?
The closing price on Sep 23, 2026 was $16.86. Our model-based fair value is $10.72, about −36% upside (overvalued). We carry closing prices from our data provider, not a live tick.
What should I pay attention to with Rallybio Corp right now?
The price sits above even our optimistic bull case ($13.40). The favourable scenario is already priced in. The large gap to fair value rests on thin data (low evidence): fewer applicable models and a shorter history. Read it with extra caution. Solid but not exceptional quality (60/100) and above fair value, neither a clear bargain nor a standout compounder. A fairly wide model range ($7.07 to $13.40) leaves room in how you read the outcome.

Key figures of Rallybio Corp

How large is the market capitalisation of Rallybio Corp (RLYB)?
The market capitalisation of Rallybio Corp is $97.8M. 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 are the earnings per share of Rallybio Corp (RLYB)?
Earnings per share at Rallybio Corp are $7.99 (price ÷ EPS = P/E 2.1). Earnings per share over the last twelve months: total profit spread across every single share.
What is the net margin of Rallybio Corp (RLYB)?
The net margin of Rallybio Corp is 7,051% (last twelve months). How much of every unit of revenue ends up as profit. 10% means 10 cents of profit per dollar of sales.
What is the return on equity of Rallybio Corp (RLYB)?
The return on equity (ROE) of Rallybio Corp is 64.9% (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 Rallybio Corp (RLYB)?
On an EBIT basis the return on assets of Rallybio Corp is −53.0% (avg 5y). 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 Rallybio Corp (RLYB)?
The operating margin of Rallybio Corp is −3,935% (last twelve months). Profit from the core business (before interest and taxes) relative to revenue.
How much free cash flow does Rallybio Corp (RLYB) generate?
The free cash flow of Rallybio Corp is −$29.8M (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 Rallybio Corp (RLYB) hold?
Rallybio Corp holds more cash than debt, $31.2M net (fiscal year 2025). The company holds more cash than debt, a safety cushion.
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