Rene Russo - 31 Dec 2025 Form 4 Insider Report for Xilio Therapeutics, Inc. (XLO)

Reporting relationship: PRESIDENT AND CEO, Director
Issuer ticker: XLO
Reported as of: 31 Dec 2025
Net transaction value: $0
SEC form: 4
Accepted by SEC: 05 Jan 2026, 16:30:18 UTC
Prior SEC filing: 25 Nov 2025
Source filing: View source filing
Reporting owner signature: /s/ Kevin Brennan, Attorney-in-Fact

Key filing fact

Rene Russo filed Form 4 for Xilio Therapeutics, Inc. (XLO) on 05 Jan 2026.

Key facts

This page summarizes Rene Russo's Form 4 filing for Xilio Therapeutics, Inc. (XLO).
3 reported transactions and 2 derivative rows are listed below.
Accepted by SEC: 05 Jan 2026, 16:30.

Change

Previous filing in this sequence was filed on 25 Nov 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001722066 Primary reporting owner

Russo Rene

Relationship: PRESIDENT AND CEO, Director
Address: 828 WINTER STREET, SUITE 300, WALTHAM
Signature: /s/ Kevin Brennan, Attorney-in-Fact
Signature date: 05 Jan 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

XLO transaction

Common Stock

Options Exercise

Transaction value
Shares: +44,250
Change %: +16%
Price
Shares after: 325,422
Date: 01 Jan 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

XLO transaction Derivative

Stock Option (right to buy)

Award

Transaction value: $0
Shares: +1,500,258
Change %
Price: $0.000000
Shares after: 1,500,258
Date: 31 Dec 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,500,258
Exercise price: $0.8410
Footnotes: F2, F3, F4

XLO transaction Derivative

Restricted Stock Units

Options Exercise

Transaction value: $0
Shares: -44,250
Change %: -33%
Price: $0.000000
Shares after: 88,500
Date: 01 Jan 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 44,250
Exercise price
Footnotes: F1, F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

Restricted stock units ("RSUs") convert to stock on a one-for-one basis.

Footnote F2

On October 8, 2025, the Board of Directors (the "Board") approved the adoption of the Xilio Therapeutics, Inc. 2025 Stock Incentive Plan (the "2025 Plan"), subject to stockholder approval of the adoption of the 2025 Plan. On October 8, 2025, the Compensation Committee of the Board granted these options (referred to as "Tranche 3 Options" in the 2025 Plan) to the Reporting Person, subject to stockholder approval of the adoption of the 2025 Plan. The stockholders approved the adoption of the 2025 Plan on November 21, 2025. On December 31, 2025, the performance criteria for a portion of the Tranche 3 Options was met.

Footnote F3

The portion of Tranche 3 Options that achieved the vesting condition is equal to the percentage of the Series B Warrants exercised and/or cancelled due to the receipt by Xilio Therapeutics, Inc. of Non-Dilutive Capital (as defined in the Series B Warrants) by December 31, 2025.

Footnote F4

This option vests in three (3) equal annual installments over the three-year period beginning on December 31, 2025, subject to the Reporting Person's continued service to the registrant through each applicable vesting date.

Footnote F5

These RSUs were granted on January 1, 2024 and vest in four equal annual installments beginning on January 1, 2025.