Pro Rata Side Letter (US) by Y Combinator

Open Legal LibraryUpdated 6 Oct 2025

The Pro Rata Agreement gives investors the right to purchase their proportional share of preferred stock in a company’s future equity financing, protecting them from dilution when a post-money SAFE converts. It sets out how pro rata rights are calculated, when they terminate, and rules for assignment and amendments. This agreement is part of Y Combinator’s publicly available library of standard financing documents, widely trusted and used by startups and investors.

[company name]

PRO RATA AGREEMENT

This agreement (this “Agreement”) is entered into on or about [effective date] in connection with the purchase by [investor name] (the “Investor”) of that certain simple agreement for future equity with a “Post-Money Valuation Cap” (the “Investor’s Safe”) issued by [company name] (the “Company”) on or about the date of this Agreement. As a material inducement to the Investor’s investment, the Company agrees to the provisions set forth in this Agreement. Capitalized terms used herein shall have the meanings set forth in the Investor’s Safe.

The Investor shall have the right to purchase its pro rata share of Standard Preferred Stock being sold in the Equity Financing (the “Pro Rata Right”). Pro rata share for purposes of this Pro Rata Right is the ratio of (x) the number of shares of Capital Stock issued from the conversion of all of the Investor’s Safes with a “Post-Money Valuation Cap” to (y) the Company Capitalization. The Pro Rata Right described above shall automatically terminate upon the earlier of (i) the initial closing of the Equity Financing; (ii) immediately prior to the closing of a Liquidity Event; or (iii) immediately prior to the Dissolution Event.

Neither this Agreement nor the rights contained herein may be assigned, by operation of law or otherwise, by Investor without the prior written consent of the Company; provided, however, that this Agreement and/or the rights contained herein may be assigned without the Company’s consent by the Investor to any other entity who directly or indirectly, controls, is controlled by or is under common control with the Investor, including, without limitation, any general partner, managing member, officer or director of the Investor, or any venture capital fund now or hereafter existing which is controlled by one or more general partners or managing members of, or shares the same management company with, the Investor.

Any provision of this Agreement may be amended, waived or modified upon the written consent of the Company and either (i) the holders of a majority of shares of Capital Stock issued from all Safes converted in connection with the Equity Financing held by the Investor and other Safe holders with Pro Rata Rights pursuant to agreements on the same form as this Agreement (available at http://ycombinator.com/documents), provided that such amendment, waiver or modification treats all such holders in the same manner, or (ii) the Investor. The Company will promptly notify the Investor of any amendment, waiver or modification that the Investor did not consent to. This Agreement is the form available at http://ycombinator.com/documents and the Company and the Investor agree that neither one has modified the form, except to fill in blanks and bracketed terms. The choice of law governing any dispute or claim arising out of or in connection with this Agreement shall be consistent with that set forth in the Investor’s Safe.

IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed and delivered.

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About this template

What is this template?

This document is a supplemental agreement to a Y Combinator SAFE that specifically defines participation rights in future financings. It is not a standalone investment instrument and requires an existing 'Investor's Safe' to provide the underlying definitions and governing law.

When should you use it?

Use this side letter when an investor is using the standard Y Combinator Post-Money SAFE and requires the right to maintain their ownership percentage. Use a 'Side Letter (General)' if you need to include additional custom rights like information rights or board observer seats.

What's inside

ClauseNameWhat it does
Paragraph 2Pro Rata RightGrants the Investor the right to purchase a share of Standard Preferred Stock based on the ratio of converted SAFE shares to Company Capitalization.
Paragraph 2TerminationEnds the Pro Rata Right upon the closing of an Equity Financing, Liquidity Event, or Dissolution Event.
Paragraph 3AssignmentRestricts Investor assignment without Company consent except to affiliated entities or venture capital funds under common control.
Paragraph 4Amendment and WaiverRequires written consent from the Company and either the Investor or a majority of similar SAFE holders.
Paragraph 4Governing LawDirects that the choice of law remains consistent with the law specified in the Investor's original SAFE document.

Who it's for

  • an early-stage company issuing a post-money SAFE to a venture capital investor
  • an investor requiring contractual rights to participate in future equity rounds to prevent dilution

How long it runs and how it's signed

How long
Runs until the work is done
Signed by
Company, Investor
Witness
Not required
Notarisation
Not required

United States note

This version is drafted for US law generally. Contract, employment and consumer rules vary by state — for example on non-competes and at-will employment. Tell GitLaw which state applies and it adjusts the draft.

Jurisdiction
United States of America
Source
Pro Rata Side Letter (US) by Y Combinator
from Y Combinator
Document info
HTML document. Document created on Fri Sep 26th, 2025. Last updated on Mon Oct 6th, 2025.
This document is public
Licensed under CC BY 4.0 (Attribution).
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