Insider Trading February 4, 2026

Spero Therapeutics CFO Sells Shares to Cover Taxes Amid RSU and Option Grants

CEO/CFO Esther Rajavelu transacts shares and receives equity awards as Spero advances regulatory and corporate updates

By Leila Farooq SPRO
Spero Therapeutics CFO Sells Shares to Cover Taxes Amid RSU and Option Grants
SPRO

Esther Rajavelu, who serves as Chief Executive Officer, Chief Financial Officer and Chief Business Officer at Spero Therapeutics (NASDAQ: SPRO), sold 18,442 shares on February 2, 2026 to satisfy tax withholding tied to vested restricted stock units, while also receiving a grant of restricted stock units and stock options the same day. The company reported a market capitalization near $128 million and a balance sheet with more cash than debt, and disclosed several corporate developments including a board resignation, a closed SEC inquiry, and a potential $25 million milestone tied to a resubmitted NDA for tebipenem HBr.

Key Points

  • Esther Rajavelu sold 18,442 shares at $2.20 on February 2, 2026 to cover tax withholding related to vested restricted stock units.
  • On the same day Rajavelu received 249,000 restricted stock units (value reported as $0) and options to buy 498,000 shares at an exercise price of $2.23; she now directly owns 1,100,008 shares.
  • Corporate and regulatory developments include a board resignation, the SEC closing an inquiry with no enforcement action, and a resubmitted NDA for tebipenem HBr that is expected to trigger a $25 million milestone payment in Q1 2026 - affecting biotech and capital markets sectors.

Esther Rajavelu, who occupies the roles of Chief Executive Officer, Chief Financial Officer and Chief Business Officer at Spero Therapeutics (NASDAQ: SPRO), executed a share sale on February 2, 2026, disposing of 18,442 common shares at $2.20 per share. The transaction totaled $40,572 and was made to satisfy tax withholding obligations related to the vesting of restricted stock units (RSUs).

On that same date Rajavelu was the recipient of additional equity awards. The company reported a grant of 249,000 restricted stock units to Rajavelu with a stated value of $0, and a separate grant of options to purchase 498,000 shares of common stock at an exercise price of $2.23. InvestingPro’s Fair Value assessment places the option exercise price near its valuation estimate, indicating the options are priced close to what InvestingPro considers fair value.

Spero’s share price is currently trading at $2.29, and the company’s market capitalization stands at about $128 million. InvestingPro data cited by the company indicates Spero holds more cash than debt on its balance sheet. The stock has produced a 161% return over the past year despite the company’s ongoing profitability challenges.

After completing these transactions, Rajavelu directly holds 1,100,008 shares of Spero Therapeutics. Analysts covering the company have set a price target of $4.00 per share.

In addition to the insider transactions and equity awards, Spero provided several corporate updates. The company announced the immediate resignation of Ankit Mahadevia from its Board of Directors; Mahadevia also stepped down from the Development Committee and other roles within Spero’s subsidiaries, citing other professional commitments as the reason for his departure.

Spero also disclosed that an SEC inquiry has been closed, with the regulatory body electing not to pursue enforcement action against the company. Separately, GSK has resubmitted a New Drug Application to the U.S. Food and Drug Administration for Spero’s investigational antibiotic tebipenem HBr. That resubmission is tied to a $25 million milestone payment to Spero, which the company anticipates receiving in the first quarter of 2026.

InvestingPro has identified additional details about Spero’s financial position and outlook in its Pro Research Report, which covers more than 1,400 U.S. equities. The report and the Fair Value assessment referenced are noted by InvestingPro as tools for evaluating the company’s valuation and financial metrics.


Contextual note - The equity transactions reported for Rajavelu consisted of a small sale to meet tax obligations arising from vested RSUs, the issuance of RSUs with a book value of $0, and a significant option grant priced near InvestingPro’s Fair Value estimate. The company’s corporate updates include governance changes, a closed SEC inquiry, and a regulatory milestone event tied to a potential $25 million payment expected in early 2026.

Risks

  • Profitability challenges - the company faces ongoing profitability issues, which could influence financial performance and investor sentiment in the biotech sector.
  • Milestone timing and receipt - the $25 million milestone payment tied to the resubmitted NDA for tebipenem HBr is anticipated in Q1 2026, creating uncertainty around the timing and realization of that cash inflow.
  • Equity dilution and compensation effects - significant issuance of RSUs and option grants increases outstanding potential shares, which can affect existing shareholder dilution and capital structure in the markets sector.

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