Shares outstanding are shares that have been authorized, issued, and purchased by investors and are held by them. Spero Therapeutics's shares outstanding for the quarter that ended in Mar. 2026 was 57.89 Mil.
Spero Therapeutics's quarterly shares outstanding
increased
from Dec. 2025 (56.42 Mil) to Mar. 2026 (57.89 Mil).
It means Spero Therapeuticsissued new shares from Dec. 2025 to Mar. 2026 .
Spero Therapeutics's annual shares outstanding
increased
from Dec. 2024 (54.59 Mil) to Dec. 2025 (56.42 Mil).
It means Spero Therapeuticsissued new shares from Dec. 2024 to Dec. 2025 .
A company may buy back shares or issue shares in any fiscal period. If a company buys back shares, we should observe that the total number of shares decline. If the company issues new shares, the number of shares outstanding increases.
Usually the presence of treasury shares and a history of buyback are good indicators that company has competitive advantage. But studies have shown that companies usually buy back at wrong time. Buying back shares below its intrinsic value increases value for remaining shareholders. Buying back overvalued shares destroys value for existing shareholders.
Be Aware
Warren Buffett looks for consistency and upward long term trend. Because of share repurchase it is possible for net earnings trend to differ from EPS trend. He preferred net income over EPS. The companies with durable competitive advantage companies report higher % net earnings to total revenues.
Important: If a company is showing net earnings history greater than 20% on total revenues, it is probably benefiting from a long term competitive advantage.
If net earnings is less than 10%, likely to be in a highly competitive business.
Spero Therapeutics Shares Outstanding (EOP) Related Terms
Spero Therapeutics Shares Outstanding (EOP) Historical Data
* Premium members only.
The historical data trend for Spero Therapeutics's Shares Outstanding (EOP) can be seen below:
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
SPRO vs ORMP, PLYX, HRTX: Shares Outstanding (EOP) Comparison
For the Biotechnology subindustry, Spero Therapeutics's Shares Outstanding (EOP), along with its competitors' market caps and Shares Outstanding (EOP) 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 Shares Outstanding (EOP) vs Biotechnology Industry
For the Biotechnology industry and Healthcare sector, Spero Therapeutics's Shares Outstanding (EOP) distribution charts can be found below:
* The bar in red indicates where Spero Therapeutics's Shares Outstanding (EOP) falls into.
Shares outstanding are shares that have been authorized, issued, and purchased by investors and are held by them. They have voting rights and represent ownership in the corporation by the person that holds the shares. They should be distinguished from treasury shares, which are shares held by the corporation itself, having no exercisable rights.
Shares outstanding can be calculated as either basic or fully diluted. The fully diluted shares outstanding count includes diluting securities, such as options, warrants or convertibles.
What does a Shares Outstanding (EOP) of 57.89 Mil mean?
Spero Therapeutics (SPRO) has a Shares Outstanding (EOP) of 57.89 Mil as of Mar. 2026. The total shares a company has outstanding, at period-end. View historical data on Spero Therapeutics and its competitors.
Is Spero Therapeutics' Shares Outstanding (EOP) too high?
Spero Therapeutics' current Shares Outstanding (EOP) is 57.89 Mil. 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' Shares Outstanding (EOP) compare to ORMP and PLYX?
Spero Therapeutics' Shares Outstanding (EOP) of 57.89 Mil can be compared against companies in the Biotechnology industry. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good Shares Outstanding (EOP) for a Biotechnology company?
A good Shares Outstanding (EOP) depends on the Biotechnology industry context. However, Shares Outstanding (EOP) 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 Shares Outstanding (EOP) mean?
A high Shares Outstanding (EOP) can signal that a stock is expensive relative to its fundamentals. The total shares a company has outstanding, at period-end. View historical data on Spero Therapeutics and its competitors. Spero Therapeutics's current Shares Outstanding (EOP) is 57.89 Mil. 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 $2.02 — trading 90.6% above its estimated fair value. The current Shares Outstanding (EOP) is 57.89 Mil. 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 Shares Outstanding (EOP) calculated?
Shares Outstanding (EOP) is calculated from a company's financial statements. For Spero Therapeutics (SPRO), the current Shares Outstanding (EOP) is 57.89 Mil as of Mar. 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 $2.02 is trading 90.6% above its estimated GF Value™ of $1.06.
GuruFocus considers Spero Therapeutics to be Significantly Overvalued.
Key valuation signals for SPRO:
Shares Outstanding (EOP): 57.89 Mil
GF Value™: $1.06 vs. price of $2.02 (90.6% above fair value)
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 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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