Spero Therapeutics, Inc. (SPRO) Fair Value 2026

SPRO · Biotechnology ·

By CirclFi Research Team · Data from SEC EDGAR, FRED & GDELT

Quality Score

7.4 /10

32 fundamental signals · 8 models active

Value Trap Risk

WARN (48/100)

Quick Summary — As of 2026-08-28, Spero Therapeutics, Inc. (SPRO) trades at $1.20, versus a $1.54 median fair value across its 8 active models — 27.9% above the current price. QOC: 7.4/10. Value Trap Risk: 48/100 (WARN). 8/13 models active. Within that set, the Bayesian DCF component alone returns $1.19.

Key Facts

Ticker
SPRO
Price
$1.20
Quality Score
7.4/10
Value Trap Risk
48/100
Models Active
8/13
Last Updated
Strength: First Chicago suggests +100.8% upside with 49% confidence
Risk: Value Trap score of 48 suggests caution despite apparent undervaluation

Is Spero Therapeutics, Inc. (SPRO) Undervalued or Overvalued in 2026?

According to CirclFi’s 8-model valuation engine, Spero Therapeutics, Inc. (SPRO) appears undervalued as of : the median of 8 independent fair value estimates is $1.54, 27.9% above the current price of $1.20. Estimates range from $0.71 to $3.57. SPRO scores 7.4/10 on fundamental quality and 48/100 on value-trap risk.

For context, the median US equity CirclFi rates trades at an implied -23.4% versus its own 13-model consensus, across 3,809 rated companies as of 2026-08-28. SPRO’s +27.9% gap is wider than that market norm, and the Biotechnology sector median is -64.7%. Full market index →

This verdict compares price to intrinsic value only — it is not a buy or sell rating. For the decision case (bull vs bear arguments, risk factors, peers), read Should You Buy Spero Therapeutics, Inc. Stock in 2026? →

What Fair Value Does Each Model Give SPRO?

8 Intrinsic Value Models vs. Current Price ($1.20)

Core Models (Unlocked)
Model Fair Value Upside
Intrinsic · Medium Conviction
 $1.19 -0.6%
Ensemble · Low Conviction
 $1.58 +31.9%
Scenario · Medium Conviction
 $2.41 +100.8%
Intrinsic · Medium Conviction
 $0.71 -40.6%
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What Is SPRO's Fair Value Range?

Spread across 8 independent models · $0.71 to $3.57

CirclFi's 8 active models place Spero Therapeutics, Inc. (SPRO) between $0.71 and $3.57 per share, a spread of 186% of the median. The median of that range — $1.54 — is the fair value CirclFi publishes for SPRO, against a current price of $1.20.

Low · ML-RIVHigh · Regime Cross
$0.71median $1.54$3.57
Where the range comes from
Most bearish modelML Residual Income$0.71
Most bullish modelRegime Cross-Sectional$3.57
Model agreement5 bullish · 2 bearishwide

A band this wide is itself the finding. When independent methods land far apart, they are reading a business whose value depends heavily on which lens you apply — volatile earnings, heavy reinvestment, or an asset base that cash-flow and asset-based methods score differently. That disagreement is information: it says the choice of method matters more than usual for SPRO. Treat the median as one reading among several and compare the individual models below before acting.

Every figure above is one model's standalone output on SPRO, not a CirclFi price target. How each model works →

What Is Spero Therapeutics, Inc. (SPRO) Worth in 2026?

According to the CirclFi Deep Alpha Valuation Engine, our multi-model framework produces a cautiously optimistic read on Spero Therapeutics, Inc. at $1.20. With an estimated intrinsic value of $1.54 and 5 of 8 models pointing higher, the median implied return is +27.9%. The most optimistic model, Regime Cross, places fair value at $3.57 (+197.5%), while ML-RIV — the most conservative — estimates $0.71 (-40.6%). This +238.1% gap reflects genuine analytical uncertainty about Spero Therapeutics, Inc.'s intrinsic worth.

What Do the Models Say About SPRO?

8 of 13 models are currently active for SPRO. Of these, 5 models suggest upside while 3 models suggest overvaluation. Taken together, their median fair value for SPRO is $1.54 — the figure CirclFi publishes as this stock's fair value. One component of that median, the Bayesian DCF, returns $1.19 on its own, implying -0.6% downside from the current price. See which stocks rank higher →

How Does SPRO Rank in Biotechnology?

Among 625 Biotechnology stocks, SPRO ranks #37 by Quality of Company score. CirclFi's QOC score of 7.4/10 evaluates 32 fundamental signals. A score of 7.4 indicates above-average quality.

See all Most Undervalued Biotechnology Stocks →

The Biotechnology sector introduces analytical considerations specific to biotech businesses. For Spero Therapeutics, Inc., metrics like clinical trial success rate provide important context that general-purpose valuation models may underweight.

Is SPRO a Value Trap?

CirclFi's Value Trap algorithm assigns SPRO a score of 48/100 (WARN). This is a warning signal. Additional research into recent 10-Q filings is recommended. The score cross-references apparent undervaluation against fundamental deterioration signals. Browse lowest value-trap stocks →

Multi-Model Methodology

8 of 13 models are active for Spero Therapeutics, Inc.. Moderate coverage provides meaningful perspective. Each model applies a fundamentally different valuation philosophy. See the complete methodology →

According to the CirclFi Deep Alpha Valuation Engine, Spero Therapeutics, Inc. scores 7.4 out of 10 on our 32-signal quality assessment, a solid rating that maintains reasonable quality metrics with some areas for improvement. The QOC score synthesizes profitability margins, revenue growth reliability, debt management, and capital allocation into a single metric designed to separate durable businesses from statistically cheap ones.

The gap between the most bullish and bearish model spans +238.1% — demonstrating why single-model analysis is dangerous. Browse all stocks with 13-model coverage →

Data Sources & Confidence

Every SPRO valuation is built from SEC EDGAR XBRL filings — 700+ standardized financial tags. Macroeconomic context from FRED calibrates discount rates, while GDELT news sentiment feeds into our Sentiment SOTP model. All pipelines run daily. Read the complete data methodology →

Across SPRO's 8 active models, average confidence is 34%. Lower confidence may reflect limited history or high volatility.

CirclFi's output is a research starting point, not a buy/sell signal. All data updates daily. Read the full methodology →

This analysis is produced by the CirclFi Valuation Engine using quantitative models applied to SEC EDGAR filings, public market feeds, and FRED macroeconomic indicators. It is not financial advice.

Read the full investment analysis: Should You Buy Spero Therapeutics, Inc. Stock in 2026? →

Bull case, bear case, risk factors & peer comparison — updated daily

Which Similar Biotechnology Stocks Should You Also Analyze?

11 related Biotechnology stocks with 13-model coverage

BDTXBlack Diamond Therapeutics, Inc.QOC 7.5BNTXBioNTech SEQOC 7.3JAZZJazz Pharmaceuticals plcQOC 7.6TLXTelix Pharmaceuticals LimitedQOC 7.2ARWRArrowhead Pharmaceuticals, Inc.QOC 7.6ARVNArvinas, Inc.QOC 7.2WHWKWhitehawk Therapeutics, Inc.QOC 5.7FBLGFibroBiologics, Inc.QOC 4.9BBLGBone Biologics CorporationQOC 4.2EXELExelixis, Inc.QOC 9.6INCYIncyte CorporationQOC 9.5

Read investment analysis: BDTX · BNTX · JAZZ · TLX · ARWR · ARVN · WHWK · FBLG · BBLG · EXEL · INCY

Which Other Stocks Have a Similar Quality Score to SPRO?

7 companies across all industries closest to SPRO’s Quality of Company score of 7.4/10.

NSLRNeostellar Capital Corp.QOC 7.4ROGRogers CorporationQOC 7.4TACTTransAct Technologies IncorporatedQOC 7.4IPIIntrepid Potash, Inc.QOC 7.4SCLStepan CompanyQOC 7.4DKNGDraftKings Inc.QOC 7.4NVDANVIDIA CorporationQOC 10.0

Read investment analysis: NSLR · ROG · TACT · IPI · SCL · DKNG · NVDA

Where Does SPRO Sit in CirclFi's Biotechnology Rankings?

SPRO is ranked against every other Biotechnology stock CirclFi covers in each of these screens.

See all Biotechnology stocks ranked →

What Else Do Investors Ask About Spero Therapeutics, Inc.’s Valuation?

What is Spero Therapeutics, Inc.'s intrinsic value in 2026?

CirclFi puts Spero Therapeutics, Inc. (SPRO)'s intrinsic value at $1.54 — the median of 8 independent model estimates as of 2026-08-28, ranging from $0.71 to $3.57. One component of that median, the Bayesian DCF, runs 10,000 Monte Carlo simulations with jump-diffusion and returns $1.19 on its own. The Quality of Company score is 7.4/10 across 32 fundamental signals. All models use SEC EDGAR filings updated daily. See our methodology page for how each model works.

Is SPRO overvalued or undervalued right now?

At $1.20, 5 of 8 active models suggest SPRO may be undervalued, while 3 indicate potential overvaluation. The median of all 8 fair value estimates is $1.54, 27.9% above the current price of $1.20 — a consensus view that SPRO is undervalued. The assessment depends on which methodology best fits Spero Therapeutics, Inc.'s business model in Biotechnology.

What does a Quality of Company score of 7.4 mean for SPRO?

Spero Therapeutics, Inc.'s QOC of 7.4/10 reflects 32 fundamental signals: profitability margins, revenue growth consistency, balance sheet leverage, free cash flow generation, and capital allocation efficiency. Scores above 7 indicate strong fundamentals and disciplined management.

How many valuation models does CirclFi run on SPRO?

CirclFi analyzes SPRO with 13 institutional-grade models daily: Bayesian DCF (Monte Carlo + jump-diffusion), EPV (Greenwald zero-growth), EROIC Spread (McKinsey reinvestment), First Chicago (3-scenario), Markov DDM (regime-switching), ML-RIV (machine learning residual income), Dynamic NAV (asset-based), PWERM (option-theoretic), Regime Cross-Sectional (relative), Sentiment SOTP (hybrid), CUCE Ensemble (meta-model), FTNN Topology (neural network), and RCMH-DCF (conditional regime). Currently 8 of 13 are active for this stock. Read the full methodology →

Which valuation models are most bullish and most bearish on SPRO?

Of the 8 models currently active on SPRO, Regime Cross-Sectional is the most bullish at $3.57 per share, and ML Residual Income is the most bearish at $0.71. CirclFi's published fair value for SPRO is the median of that range, $1.54, not either extreme. The gap between the two ends equals 186% of the median — a wide spread, meaning the methods genuinely disagree and the median should carry less weight. Browse stocks by value-trap risk →

Is SPRO a value trap in 2026?

Spero Therapeutics, Inc.'s Value Trap score is 48/100 (WARN). This elevated score suggests the stock may look undervalued but faces deteriorating fundamentals — declining margins, rising debt, or shrinking revenue could make the apparent discount deceptive. Browse our ranked stock lists to compare value-trap scores across industries.

Cite this analysis — “According to CirclFi’s 8-model valuation engine, Spero Therapeutics, Inc. (SPRO) has a median fair value of $1.54 — 27.9% above the current price of $1.20 — as of 2026-08-28.” Source: circlfi.com/stock/SPRO/ · Methodology
Primary sources for this SPRO valuation
  • Financial statements: Spero Therapeutics, Inc. 10-K and 10-Q filings on SEC EDGAR (CIK 0001701108) — 700+ standardized XBRL tags, published by the U.S. Securities and Exchange Commission.
  • Discount-rate inputs: FRED, Federal Reserve Bank of St. Louis — risk-free rates, VIX, yield curve, inflation.
  • News sentiment: The GDELT Project — global media tone, input to the Sentiment SOTP model.
  • Model definitions: CirclFi methodology — the published specification for all 13 models, including the academic sources each one implements.

Market data for SPRO as of ; valuations recomputed .

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