Spero Therapeutics grants William Ho 100,000 options

The option has a $1.01-per-share exercise price and expires November 10, 2036.

Available on EDGAR 11/10/2026 - 06:27 PM EST Accepted by SEC EDGAR 11/10/2026 - 06:26 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Spero Therapeutics, Inc. director William Ho received a stock-option award covering 100,000 common shares on November 10, 2026. The underlying shares vest in equal monthly installments until the third anniversary of the grant date, subject to his continued service through each applicable vesting date.

Insider Trade Summary

Grant/Award: 100,000 shares

Grant/Award 1 txn

Insider HO WILLIAM

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy) F1	100,000	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 100,000 options (Direct)

Footnotes (1)

1. F1. The shares underlying this option shall vest in equal monthly installments until the third anniversary of the grant date, subject to the Reporting Person's continued service through the applicable vesting date.

Key Figures

Underlying common shares: 100,000 shares Exercise price: $1.01 per share Expiration date: November 10, 2036 +1 more

4 metrics

Underlying common shares 100,000 shares Stock-option award to William Ho on November 10, 2026

Exercise price $1.01 per share Stock option

Expiration date November 10, 2036 Stock option

Vesting schedule Equal monthly installments until the third anniversary of the grant date Subject to continued service through each applicable vesting date

Key Terms

Stock Option (right to buy), exercise price, vest

3 terms

Stock Option (right to buy) financial

"Stock Option (right to buy)"

exercise price financial

"exercise price of $1.01 per share"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

vest technical

"shall vest in equal monthly installments"

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many SPRO shares does William Ho's option cover?

William Ho's stock option covers 100,000 common shares.

What are the SPRO option exercise price and expiration date?

The option has a $1.01-per-share exercise price and expires on November 10, 2036.

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

Form 4 Insider Transactions: What Each Field Means →

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SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

HO WILLIAM

(Last) (First) (Middle)

C/O 675 MASSACHUSETTS AVENUE

14TH FLOOR

(Street)

CAMBRIDGE MASSACHUSETTS 02139

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Spero Therapeutics, Inc. [ SPRO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
11/10/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$1.01	11/10/2026		A		100,000		(1)	11/10/2036	Common Stock	100,000	$0.00	100,000	D

Explanation of Responses:

1. The shares underlying this option shall vest in equal monthly installments until the third anniversary of the grant date, subject to the Reporting Person's continued service through the applicable vesting date.

	/s/ Maegan Deare, Attorney-in-Fact for William Ho	11/10/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)