SPRO (Spero Therapeutics) GF Value Rank: 1 (As of Jul. 01, 2026) — 50% Below Median


SPRO Spero Therapeutics Inc SPRO
55 GF Score
Price $2.22
GF Value $1.06
Valuation Significantly Overvalued
! 4 Warning Signs
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What is Spero Therapeutics GF Value Rank?

Spero Therapeutics SPRO +0.68% 55 GF Value Rank is 1 as of Jul. 01, 2026, which is 50% below its 10-year median of 2.00. GuruFocus rates SPRO with a GF Score™ of 55/100 and a GF Value™ of $1.06 (Significantly Overvalued). The stock has 4 warning signs investors should review.

Spero Therapeutics has the GF Value Rank of 1.

GF Value Rank evaluates the exclusive GuruFocus valuation and performance of a stock, rated on a scale from 1 to 10. It is determined by the price-to-GF-Value (P/GF Value) ratio, a proprietary metric calculated based on historical multiples along with an adjustment factor based on a company's past returns and growth and future estimates of the business' performance.

GuruFocus found that for valuation, we cannot simply give stocks a better GF Value rank simply because they have a lower P/GF Value ratio. Backtesting shows that over the long term, the two worst-performing groups are the most expensive group (with the highest P/GF Value ratio) and the least expensive group (with the lowest P/GF Value ratio).

We can understand why the most expensive group underperforms. We were initially puzzled by the underperformance of the least expensive group, but we realized there is a reason why some stocks are super cheap. If they look too undervalued, it is often because the businesses behind them are poor quality. The market realized this and gave them low valuations. In a way, the market is efficient.

After multiple backtesting analyses, we granted the stocks in third-cheapest percentile the highest GF Value rank, as they have performed the best over a full market cycle. Stock performance is actually not as sensitive to valuation as it is to growth and profitability. On average, the companies in the 20%-50% valuation groups have similar performances. Therefore, we should avoid the most expensive and the least expensive stocks. We can be more tolerant of valuation.

A higher score indicates a stock with a relatively low valuation and substantial potential for outperformance. Conversely, a lower score often reflects stocks that are either highly overvalued or deeply undervalued, both of which tend to underperform.

Please click GF Score to see more details on the GF Score's 5 Key Aspects of Analysis.

Spero Therapeutics GF Value Rank Related Terms

SPRO vs VXRT, ADCT, GNLX: GF Value Rank Comparison

For the Biotechnology subindustry, Spero Therapeutics's GF Value Rank, along with its competitors' market caps and GF Value Rank data, can be viewed below:

* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.

Spero Therapeutics GF Value Rank vs Biotechnology Industry

For the Biotechnology industry and Healthcare sector, Spero Therapeutics's GF Value Rank distribution charts can be found below:

* The bar in red indicates where Spero Therapeutics's GF Value Rank falls into.


SPRO
55GF Score
Spero Therapeutics Inc SPRO
GF Value Rank is just one metric. See GF Score™, valuation, warning signs, and more.
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Frequently Asked Questions Learn more about GF Value Rank →
What does a GF Value Rank of 1 mean?
Spero Therapeutics (SPRO) has a GF Value Rank of 1 as of Jul. 01, 2026. GF Value Rank is given based on historical multiples along with past returns, growth and future estimates of the business' performance. View historical data on Spero Therapeutics and its competitors. This is 50% below median its historical median of 2.00. Over the past decade, Spero Therapeutics' GF Value Rank has ranged from 1.00 to 10.00.
Is Spero Therapeutics' GF Value Rank too high?
Spero Therapeutics' current GF Value Rank of 1 is 50% below median its 10-year median of 2.00. Over the past 10 years, this metric has ranged from a low of 1.00 to a high of 10.00. Overall, Spero Therapeutics has a GF Score™ of 55/100 and is considered Significantly Overvalued, reflecting its overall financial health beyond just this single metric.
How does Spero Therapeutics' GF Value Rank compare to VXRT and ADCT?
Spero Therapeutics' GF Value Rank of 1 can be compared against companies in the Biotechnology industry. Historically, Spero Therapeutics' own GF Value Rank has ranged from 1.00 to 10.00 over the past decade. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good GF Value Rank for a Biotechnology company?
A good GF Value Rank depends on the Biotechnology industry context. However, GF Value Rank should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high GF Value Rank mean?
A high GF Value Rank can signal that a stock is expensive relative to its fundamentals. GF Value Rank is given based on historical multiples along with past returns, growth and future estimates of the business' performance. View historical data on Spero Therapeutics and its competitors. Spero Therapeutics's current GF Value Rank is 1, which is 50% below median its own 10-year median of 2.00. However, context matters — high-growth companies often justify higher valuations. Always evaluate alongside other metrics like GF Score™ and GF Value™.
Is Spero Therapeutics stock overvalued right now?
Based on GuruFocus' analysis, Spero Therapeutics (SPRO) is currently considered Significantly Overvalued. The stock's GF Value™ is $1.06, compared to a current price of $2.22 — trading 109.4% above its estimated fair value. The current GF Value Rank is 1, which is 50% below median its 10-year median of 2.00. Spero Therapeutics' overall GF Score™ is 55/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is GF Value Rank calculated?
GF Value Rank is calculated from a company's financial statements. For Spero Therapeutics (SPRO), the current GF Value Rank is 1 as of Jul. 01, 2026. GuruFocus calculates this using data sourced from SEC filings and annual reports. See the calculation section and 30-year financial data on this page for the full breakdown.

Is Spero Therapeutics (SPRO) Overvalued in 2026?

Based on GuruFocus' analysis, Spero Therapeutics stock appears to be overvalued. The current stock price of $2.22 is trading 109.4% above its estimated GF Value™ of $1.06. GuruFocus considers Spero Therapeutics to be Significantly Overvalued.

Key valuation signals for SPRO:

  • GF Value Rank: 1 (50% below median its 10-year median of 2.00)
  • GF Value™: $1.06 vs. price of $2.22 (109.4% above fair value)
  • GF Score™: 55/100 with 4 warning signs

No single metric tells the full story. See the SPRO stock analysis page for a complete view including 30-year financials, guru trades, and insider activity.

Spero Therapeutics Business Description

Other Exchanges 2HA:Germany
Address 675 Massachusetts Avenue, 14th Floor, Cambridge, MA, USA, 02139
Spero Therapeutics Inc is a clinical-stage biopharmaceutical firm. It focuses on identifying, developing, and commercializing novel treatments for MDR (Multi-drug-resistant) bacterial infections and rare diseases. The company's product candidate, tebipenem pivoxil hydrobromide or tebipenem HBr, is designed to be an oral carbapenem-class antibiotic for use in adults to treat MDR Gram-negative infections. It is also developing SPR720, a novel oral antibiotic designed for the treatment of a rare, orphan disease caused by pulmonary non-tuberculous mycobacterial infections, or NTM disease. It is also focused on SPR206, a next-generation polymyxin investigational product candidate being developed as an IV-administered medicine to treat MDR Gram-negative infections in the hospital.
55GF Score

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GF Value Rank is just one metric. See GF Value™, 30-year financials, guru trades, warning signs, and more.

$2.22
Price
$1.06
GF Value