Spero Therapeutics (NASDAQ: SPRO) doubles share authorization and adopts 2026 stock plan

Rhea-AI Filing Summary

Spero Therapeutics, Inc. held its 2026 annual meeting of stockholders, where stockholders approved a new 2026 Stock Incentive Plan covering up to 12,895,866 shares of common stock. This plan will be used for future equity awards to employees, directors, and other service providers.

Stockholders also approved an amendment to the Amended and Restated Certificate of Incorporation to increase authorized common stock from 120,000,000 shares to 240,000,000 shares, expanding the capacity for future issuances. A quorum of 41,061,190 shares, or about 70.91% of the 57,901,493 shares outstanding as of April 24, 2026, was present, and director nominees and other proposals received the required support.

Insights

Equity & Governance Analyst

Spero expands equity capacity with a new incentive plan and doubled authorized shares.

Spero Therapeutics gained stockholder approval for a 2026 Stock Incentive Plan covering up to 12,895,866 shares and doubled its authorized common stock to 240,000,000 shares. This combination increases flexibility to grant equity compensation and potentially raise capital through future share issuances.

These actions do not themselves issue new shares but set the framework for future dilution as awards are granted or capital raises occur. The annual meeting was well attended, with about 70.91% of 57,901,493 shares outstanding as of April 24, 2026 counted toward quorum, and director elections and proposals received strong support.

8-K Event Classification

4 items: 5.02, 5.03, 5.07, 9.01

4 items

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers Governance

Key personnel changes including departures, elections, or appointments of directors and executive officers.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year Governance

The company amended its charter documents, bylaws, or changed its fiscal year.

Item 5.07 Submission of Matters to a Vote of Security Holders Governance

Results of a shareholder vote on proposals at an annual or special meeting.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

2026 Plan share pool: 12,895,866 shares Authorized common stock after amendment: 240,000,000 shares Authorized common stock before amendment: 120,000,000 shares +4 more

7 metrics

2026 Plan share pool 12,895,866 shares Maximum shares issuable under 2026 Stock Incentive Plan

Authorized common stock after amendment 240,000,000 shares Total authorized common stock under amended charter

Authorized common stock before amendment 120,000,000 shares Authorized common stock prior to June 23, 2026 amendment

Shares outstanding on record date 57,901,493 shares Common stock issued and outstanding as of April 24, 2026

Quorum shares present 41,061,190 shares Shares present in person or by proxy at annual meeting

Quorum percentage 70.91% Portion of outstanding shares represented at annual meeting

Votes for key proposal 40,866,196 votes One proposal vote total For, with 189,300 Against and 5,694 Abstained

Key Terms

2026 Stock Incentive Plan, Amended and Restated Certificate of Incorporation, Broker Non-Votes, quorum, +1 more

5 terms

2026 Stock Incentive Plan financial

"stockholders approved the Spero Therapeutics, Inc. 2026 Stock Incentive Plan (the “2026 Plan”)"

Amended and Restated Certificate of Incorporation regulatory

"approved an amendment to the Company’s Amended and Restated Certificate of Incorporation"

A company’s amended and restated certificate of incorporation is an updated version of its foundational legal charter that replaces the older document and folds in all changes into one clear copy; it spells out corporate structure, classes of stock, shareholder rights and key governance rules. Investors care because it can change who controls the company, how votes are counted, what claims shareholders have on assets or dividends, and can introduce or remove protections against takeovers—like updating a house title after a major renovation to show who owns what and under what rules.

Broker Non-Votes financial

"Votes For | | Votes Against | | Votes Abstained | | Broker Non-Votes"

Broker non-votes occur when a brokerage firm is unable to vote on a shareholder’s behalf during a company election or decision because the shareholder has not given specific voting instructions, and the broker is not allowed or chooses not to vote on certain matters. They are important because they can affect the outcome of votes, especially when the results are close, by effectively reducing the total number of votes cast.

quorum financial

"a quorum of 41,061,190 shares, or approximately 70.91% of the outstanding shares, were present"

A quorum is the minimum number of members needed to officially hold a meeting or make decisions. It ensures that decisions are made with enough participation to represent the group’s interests, much like a majority must be present for a vote to be valid. For investors, understanding quorum is important because it affects when and how important company or organization decisions can be legally made.

Certificate of Amendment regulatory

"The certificate of amendment to the Company’s Amended and Restated Certificate of Incorporation (the “Certificate of Amendment”)"

A certificate of amendment is an official filing that updates a company’s founding documents—its legal “rulebook” that sets share structure, voting rules, name and basic purpose. Think of it like changing the blueprint of a building: small changes are paperwork, big ones can alter who owns how much and who controls decisions. Investors watch these filings because they can affect share counts, voting power, dilution and company value.

FAQ

What did Spero Therapeutics (SPRO) stockholders approve at the 2026 annual meeting?

Stockholders approved the 2026 Stock Incentive Plan and an amendment doubling authorized common stock to 240,000,000 shares. They also elected directors and passed other proposals with the necessary voting support.

How many shares are reserved under Spero Therapeutics' 2026 Stock Incentive Plan?

The 2026 Stock Incentive Plan allows issuance of up to 12,895,866 shares of common stock. These shares may be granted over time as equity awards to employees, directors, and other eligible service providers.

How many Spero Therapeutics shares are now authorized after the amendment?

Authorized common stock increased from 120,000,000 to 240,000,000 shares. This change expands the company’s ability to issue new shares in the future for financing, equity compensation, or other corporate purposes.

What was the quorum at Spero Therapeutics' 2026 annual meeting?

A quorum of 41,061,190 shares, representing approximately 70.91% of the 57,901,493 shares outstanding as of April 24, 2026, was present. This satisfied requirements to conduct official stockholder business.

Were Spero Therapeutics director nominees elected at the 2026 annual meeting?

Yes. Director nominees, including Milind Deshpande, Ph.D., and Kathleen Tregoning, received more votes "For" than "Withheld". Broker non-votes were recorded but did not prevent their election to the board.

What proposals besides the stock plan and charter amendment did SPRO investors vote on?

Investors voted on director elections and additional proposals summarized by vote totals, including 40,866,196 votes "For" on one item and 30,356,780 votes "For" on another, indicating broad support across the agenda.

AI-generated analysis. How Rhea-AI works. Not financial advice.

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Understanding 8-K Material Events →

Available on EDGAR 06/25/2026 - 05:09 PM Accepted by SEC EDGAR 06/25/2026 - 05:08 PM Learn about SEC filing dates

false 0001701108 --12-31 0001701108 2026-06-23 2026-06-23

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 23, 2026

SPERO THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware		001-38266		46-4590683
(State or other jurisdiction of incorporation)		(Commission File Number)		(I.R.S. Employer Identification No.)

675 Massachusetts Avenue, 14th Floor Cambridge, Massachusetts		02139
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code (857) 242-1600

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.001 par value		SPRO		The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

Approval of the 2026 Stock Incentive Plan

At the 2026 Annual Meeting of Stockholders (the “Annual Meeting”) of Spero Therapeutics, Inc. (the “Company”) held on June 23, 2026, the Company’s stockholders approved the Spero Therapeutics, Inc. 2026 Stock Incentive Plan (the “2026 Plan”), which had previously been adopted by the Company’s board of directors (the “Board”), subject to stockholder approval. Subject to adjustments in accordance with the 2026 Plan, up to 12,895,866 shares of common stock may be issued from time to time pursuant to the 2026 Plan.

The description of the 2026 Plan is contained on pages 49 to 59 of the Company’s proxy statement for the Annual Meeting (the “Proxy Statement”), filed with the Securities and Exchange Commission (the “SEC”) on April 27, 2026, is incorporated herein by reference. A complete copy of the 2026 Plan is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

Amendment to Articles of Incorporation

At the Annual Meeting, the stockholders of the Company approved an amendment to the Company’s Amended and Restated Certificate of Incorporation, to increase the total number of shares of common stock authorized for issuance thereunder from 120,000,000 shares to 240,000,000 shares. The certificate of amendment to the Company’s Amended and Restated Certificate of Incorporation (the “Certificate of Amendment”) was filed with the Secretary of State of the State of Delaware on June 23, 2026 and became effective upon filing.

The foregoing description is qualified in its entirety by the Certificate of Amendment, which is attached as Exhibit 3.1 and is incorporated herein by reference.

Item 5.07 Submission of Matters to a Vote of Stockholders

On June 23, 2026, the Company held its Annual Meeting. Of the 57,901,493 shares of common stock issued and outstanding and eligible to vote as of the record date of April 24, 2026, a quorum of 41,061,190 shares, or approximately 70.91% of the outstanding shares, were present in person or by proxy at the Annual Meeting.

The following actions were taken at the Annual Meeting:

1. The following nominees were reelected to serve on the Company’s board of directors as Class III directors until the Company’s 2029 annual meeting of stockholders, based on the following votes:

Name		Votes For				Votes Withheld				Broker Non-Votes
Milind Deshpande, Ph.D.			26,745,670				2,254,740				12,060,780
Kathleen Tregoning			28,259,925				740,485				12,060,780

2. The selection of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026 was ratified, based on the following votes:

Votes For		Votes Against		Votes Abstained		Broker Non-Votes
40,866,196		189,300		5,694		N/A

3. The advisory vote on the compensation of the Company’s named executive officers, as described in the Proxy Statement, was approved, based on the following votes:

Votes For		Votes Against		Votes Abstained		Broker Non-Votes
27,890,254		1,002,982		107,174		12,060,780

4. The amendment to the Company’s Amended and Restated Certificate of Incorporation to increase the total number of shares of common stock authorized for issuance thereunder from 120,000,000 shares to 240,000,000 shares, was approved, based on the following votes:

Votes For		Votes Against		Votes Abstained		Broker Non-Votes
30,356,780		10,558,645		145,765		N/A

5. The Spero Therapeutics, Inc. 2026 Stock Incentive Plan, was approved, based on the following votes:

Votes For		Votes Against		Votes Abstained		Broker Non-Votes
25,379,610		3,567,416		53,384		12,060,780

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

Exhibit No.		Description
3.1		Certificate of Amendment to Restated Certificate of Incorporation of Spero Therapeutics, Inc.
99.1		Spero Therapeutics, Inc. 2026 Stock Incentive Plan (incorporated by reference to Exhibit 99.1 of registrant’s Registration Statement on Form S-8 (File No. 333-296972) filed with the SEC on June 23, 2026)
104		Cover Page Interactive Data File (embedded within the Inline XBRL document and incorporated as Exhibit 101)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: June 25, 2026				SPERO THERAPEUTICS, INC.
				By:		/s/ Esther Rajavelu
						Esther Rajavelu
						Chief Executive Officer and Chief Financial Officer

Filing Exhibits & Attachments

4 documents

Other Documents

• EX-3.1 EX-3.1 5.0 KB
• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 18.3 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.4 KB