Spero Therapeutics Stock Leadership

SPRO Stock  USD 2.56  0.05  1.99%   
Below is a snapshot of Spero Therapeutics' ownership structure and how that base is positioned today. Institutional investors hold roughly 16.82% of Spero Therapeutics, while insiders own about 22.51%. Insider transaction patterns around earnings dates can reveal confidence or hedging behavior.
Insider Sentiment
SellingBuying
0 · Aggressively Selling
Spero Therapeutics' insiders appear positioned to sell. Overall insider sentiment for Spero Therapeutics appears strongly bearish.

Latest Trades

2026-02-06Esther RajaveluDisposed 87917 @ 2.36View
2026-02-02Esther RajaveluDisposed 18442 @ 2.2View
2025-11-07Esther RajaveluDisposed 40270 @ 2.37View
2025-08-28Ankit MahadeviaDisposed 6572 @ 1.97View
Insider trading activity in Spero Therapeutics reflects internal positioning, transaction timing, and alignment between management behavior and market conditions, while remaining subject to formal disclosure requirements under securities law. Transaction motives are not always purely directional, which is why pattern analysis across multiple insiders strengthens the signal.
  

Spero Therapeutics' Workforce Through the Years

Historical employee data for Spero Therapeutics indicates whether the business is scaling, restructuring, or stabilizing across different operating conditions. Disclosed headcount near about 40 employees warrants comparison with broader business results to identify scaling or restructuring trends. Reported workforce figures may vary across disclosures and time periods; aggregated or historical datasets can reflect different figures depending on reporting scope and methodology.
Macro event markers
 
Covid
 
Interest Hikes

Management Team Effectiveness

SPRO has return on total asset (ROA) of 4.99% suggesting that the asset base is earning positive returns for the period. This is neither notably high nor low for the sector. Spero Therapeutics also reports a return on stockholder's equity (ROE) of 16.31%, suggesting that shareholder equity is earning positive returns for the period.
Based on figures reported as of December 31, 2025, Common Stock Shares Outstanding is near current levels at 59.04 million.

Stock Institutional Investors

At micro-cap scale, institutional coverage and secondary-market liquidity are typically well established. The holder split in Spero Therapeutics separates passive index allocation from active institutional positioning. The business currently sits in the Health Care sector and the Pharmaceuticals, Biotechnology & Life Sciences industry. Watching turnover and volume trends alongside ownership data adds depth to the picture.
Shares
The Informed Momentum Company (formerly Eam Investors)2025-12-31
218.1 K
Two Sigma Advisers, Llc2025-12-31
216.6 K
State Street Corp2025-12-31
210.2 K
Ionic Capital Management Llc2025-12-31
195.9 K
Gsa Capital Partners Llp2025-12-31
178.9 K
Intrepid Family Office Llc2025-12-31
165 K
Jane Street Group Llc2025-12-31
158.3 K
Sei Investments Co2025-12-31
132 K
Omers Administration Corp2025-12-31
131.1 K
Gsk Plc2025-12-31
9.2 M
Pfizer Inc2025-12-31
2.4 M
Spero Therapeutics smaller-cap profile at 148.23 million shapes market structure and potential liquidity pressure during stressed periods. The business currently sits in the Healthcare sector and the Biotechnology industry. Institutional flows, insider activity, and short interest together distinguish passive index allocation from active positioning for a smaller-cap like Spero Therapeutics.

Insider Trading Activities

Insider disclosures for Spero Therapeutics show how people closest to the business are behaving as market expectations change. At micro-cap scale, institutional coverage and secondary-market liquidity are typically well established. These records work best as context, not as standalone buy-or-sell signals.
 
Timothy Keutzer 19 hours ago
Disposition of 30971 shares by Timothy Keutzer of Spero Therapeutics at 1.36 subject to Rule 16 b-3
 
Esther Rajavelu few days ago
Disposition of 25240 shares by Esther Rajavelu of Spero Therapeutics at 2.51 subject to Rule 16 b-3
 
Tregoning Kathleen over a week ago
Acquisition by Tregoning Kathleen of 35604 shares of Spero Therapeutics at 1.52 subject to Rule 16 b-3
 
Shukla Sath over a week ago
Disposition of 45093 shares by Shukla Sath of Spero Therapeutics at 1.45 subject to Rule 16 b-3
 
Mahadevia Ankit over three weeks ago
Disposition of 5912 shares by Mahadevia Ankit of Spero Therapeutics at 1.35 subject to Rule 16 b-3
 
Aquilo Capital Management, Llc over three weeks ago
Disposition of 566284 shares by Aquilo Capital Management, Llc of Spero Therapeutics at 2.2503 subject to Rule 16 b-3
 
Timothy Keutzer over three months ago
Disposition of 18652 shares by Timothy Keutzer of Spero Therapeutics at 2.36 subject to Rule 16 b-3
 
Timothy Keutzer over three months ago
Disposition of 3471 shares by Timothy Keutzer of Spero Therapeutics at 2.24 subject to Rule 16 b-3
 
Timothy Keutzer over three months ago
Disposition of 24224 shares by Timothy Keutzer of Spero Therapeutics at 2.14 subject to Rule 16 b-3
 
Esther Rajavelu over three months ago
Acquisition by Esther Rajavelu of 498000 shares of Spero Therapeutics at 2.23 subject to Rule 16 b-3
 
Shukla Sath over three months ago
Disposition of 9504 shares by Shukla Sath of Spero Therapeutics at 1.8279 subject to Rule 16 b-3
 
Tregoning Kathleen over three months ago
Acquisition by Tregoning Kathleen of 15000 shares of Spero Therapeutics subject to Rule 16 b-3

Outstanding Bonds

Corporate bonds issued by Spero Therapeutics matter because they shape interest expense, maturity risk, and the flexibility management has during tighter credit conditions. Longer-dated obligations can improve financing stability, but they also leave investors more exposed if the underlying business weakens before the debt matures.
Spero Therapeutics shows a tangible amount of outstanding shares owned by insiders. An insider is usually defined as a CEO, other corporate executive, director, or institutional investor who own at least 10% of the company's outstanding shares.
 
Shares in Circulation  
 First Issued
2016-09-30
 Previous Quarter
56.28 million
 Current Value
59.37 million
 Average Shares Outstanding
31.75 million
 Quarterly Volatility
17.93 million
Macro event markers
 
Covid
 
Interest Hikes

Holders Distribution

A large institutional presence around Spero Therapeutics deserves attention because well-resourced participants establish or unwind positions quickly enough to change the market character of the security. One practical risk is that institutions can own millions of shares, so concentrated selling can pressure the stock quickly once sentiment changes.

Market Cap and Value

Workforce Comparison

Spero Therapeutics is rated below average in number of employees compared to key competitors. The total workforce of Health Care industry is at this time estimated at about 557. Spero Therapeutics holds roughly 25 in number of employees claiming about 4% of equities under Health Care sector.
SPRO has Profit Margin (PM) of 13.0%. Similarly, it shows Operating Margin (OM) of 76.0%.

Insider Trading History

The insider trade history for Spero Therapeutics reveals whether executives were buying or selling during key price moves. Sustained buying at different price levels is a stronger signal than routine scheduled sales under 10b5-1 plans.
Buy/Sell Ratio# Purchases Trades# Sales TradesTotal Shares PurchasedTotal Shares Sold
2026-03-01
1.0
4
4
952,000
65,028
2025-03-01
0.4444
4
9
1,383,685
301,778
2024-03-01
1.0
6
6
1,554,164
229,741
2023-09-01
0.1667
1
6
266,000
58,261
2023-03-01
1.75
7
4
1,642,156
28,578
2022-09-01
1.6667
5
3
75,000
1,907,813
2021-12-01
3.0
6
2
423,493
16,000
2021-03-01
1.8
9
5
434,501
103,000
2020-12-01
0.7778
14
18
163,499
636,931
2020-09-01
0.5
3
6
3,821
7,642
2020-06-01
0.625
5
8
32,180
34,360
2020-03-01
2.0
8
4
363,928
86,966
2018-09-01
0.4286
6
14
102,822
21,352
2017-12-01
0.8438
27
32
7,433,362
29,309,446

Notable Stakeholders

Stakeholder analysis for Spero Therapeutics is useful because companies often face trade-offs among groups that want very different outcomes from the same business. In practice, stakeholder review supports awareness of the people and incentives that may be shaping key decisions behind the scenes.
Esther RajaveluCEO and President, CFO, Chief Business Officer, Treasurer & DirectorProfile
Timothy KeutzerCOOProfile
Sheila FinanSenior VP & ControllerProfile
John RaymondSenior Vice President of Finance & Business OperationsProfile
Satyavrat CFACFO TreasurerProfile
James BradyChief OfficerProfile
Ted JenkinsVP RelationsProfile
Ian CritchleyHead MicrobiologyProfile
Angela MDVP DevelProfile
MBA MDPresident, CoFounderProfile
Tamara LLMChief SecretaryProfile
Susannah WalpoleHead OperationsProfile
David HongSenior DevelopmentProfile

Management Information & Data Sources

Spero Therapeutics is a micro-cap company across Biotechnology, Pharmaceuticals, Biotechnology & Life Sciences, Health Care. Leadership tenure and executive continuity help assess whether strategic vision is being maintained across cycles. Executive background and prior track record clarify current strategic priorities. CEO is Esther Rajavelu with 25 employees and 13 reported executives.

Spero Therapeutics analytics rely on periodic company reporting and market reference feeds, with quality checks and normalization applied. Insider and management fields are mapped from published filings and company disclosures.

Editorial review and methodology oversight provided by: Gabriel Shpitalnik, Member of Macroaxis Editorial Board

Workforce Efficiency and Productivity

Workforce efficiency at Spero Therapeutics reveals how effectively labor resources are being converted into revenue and earnings over time. When applied, manpower metrics highlight whether growth is being supported by better productivity or by heavier staffing costs.

Spero Therapeutics Manpower Efficiency

Return on Spero Therapeutics Manpower

Revenue Per Employee2.4M
Revenue Per Executive4.6M
Net Income Per Employee342.9K
Net Income Per Executive659.4K
Working Capital Per Employee2.3M
Working Capital Per Executive4.5M