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What is Series AA?

The Y Combinator Series AA is a set of standardized legal documents for equity financing rounds, specifically designed for YC-funded startups raising capital from angels and early-stage investors, typically in the 250K250K-2M range.
Series AA is a lightweight preferred equity financing structure with simple terms that are generally balanced but lean toward being founder-friendly. The “AA” designation distinguishes these seed-stage documents from later “Series A” venture capital rounds.

Purpose & Philosophy

Y Combinator created Series AA documents to make equity financings:

Faster

Streamlined process reduces time from weeks to days

Simpler

Eliminates unnecessary complexity for seed-stage deals

Founder-Friendly

Balanced terms that show trust in entrepreneurs

Cost-Effective

Reduces legal fees through standardization

When to Use Series AA

Series AA documents are appropriate when:
You’ve converted SAFEs and are ready for a priced equity round
Angels want equity instead of convertible instruments
You have product-market fit and recurring revenue
Round size is 250K250K-2M from multiple angel investors
For larger rounds ($2M+) or institutional VC involvement, you may need more comprehensive documents like NVCA or Series Seed templates.

Document Package

The complete Series AA package includes six key documents:

Series AA Term Sheet

Non-binding summary of key economic and governance terms for the financing.

Key Sections

  • Amount Raised: Total size of financing round
  • Pre-Money Valuation: Company value before new investment
  • Price Per Share: Calculated from valuation and shares outstanding
  • Liquidation Preference: 1x non-participating (standard)
  • Dividends: Typically none for Series AA
  • Automatic Conversion: Upon IPO or qualified financing
  • Optional Conversion: At holder’s discretion
  • Conversion Rate: Initially 1:1 preferred to common
  • Anti-Dilution: Broad-based weighted average protection
  • Board Composition: Typically 3-5 members
  • Protective Provisions: Key decisions requiring investor approval
  • Information Rights: Regular financial reporting
  • Pro Rata Rights: Ability to maintain ownership in future rounds

What Makes It Founder-Friendly

  • 1x liquidation preference (not 2x or 3x)
  • Non-participating preferred (no “double dipping”)
  • Broad-based weighted average anti-dilution (less dilutive)
  • Minimal protective provisions

Download

Comparison: Series AA vs. Alternatives

Series AA vs. SAFE

AspectSeries AASAFE
TimingImmediate equityFuture equity
ValuationSet nowSet at future round
OwnershipClear from day oneUncertain until conversion
ComplexityModerate (6 docs)Simple (1 doc)
CostHigher legal feesMinimal legal fees
Investor RightsImmediate board/info rightsNone until conversion
Best ForEstablished startupsVery early stage
Use SAFE when: Pre-product, can’t set valuation, need to move fast
Use Series AA when: Post-product, clear valuation, ready for equity investors

Typical Terms Summary

Standard Series AA terms for a typical round:

Economics

  • Liquidation: 1x non-participating
  • Anti-dilution: Broad-based weighted average
  • Dividends: None typically
  • Conversion: 1:1 with adjustments

Control

  • Board: Typically 2 founders, 1-2 investors
  • Protective provisions: Minimal
  • Voting: As-converted basis
  • Approval rights: Major decisions only

Investor Rights

  • Information rights: Annual/quarterly
  • Pro rata: For major investors
  • Registration: Standard IPO rights
  • ROFR: On founder sales

Closing Process

Typical timeline and steps for a Series AA financing:
1

Negotiate & Sign Term Sheet

Timeline: 1-2 weeks
  • Agree on key terms with lead investor
  • Execute non-binding term sheet
  • Term sheet is starting point for documents
2

Prepare Documents

Timeline: 1-2 weeks
  • Attorney drafts documents based on term sheet
  • Customize YC templates for your specific terms
  • Prepare cap table showing post-financing ownership
3

Due Diligence

Timeline: 1-2 weeks (concurrent with docs)
  • Investors review company information
  • Legal review of corporate documents
  • Financial review of statements
  • IP review (if applicable)
4

Document Review & Negotiation

Timeline: 1 week
  • Investors review draft documents
  • Negotiate any changes (typically minimal)
  • Finalize all documents
5

Obtain Approvals

Timeline: 1-3 days
  • Execute Board Consent
  • Execute Stockholder Consent
  • Both typically via DocuSign or similar
6

Closing

Timeline: 1 day
  • All parties sign documents
  • Wire transfer of funds
  • File amended certificate with Delaware
  • Issue stock certificates
  • Update cap table
Total Timeline: Typically 4-6 weeks from term sheet to closing for a Series AA round. This is significantly faster than traditional VC rounds which can take 2-3 months.

Best Practices

Don’t raise Series AA too early. Best after:
  • You’ve launched product
  • You have some revenue or clear path to revenue
  • You can justify a reasonable valuation
  • You’ve converted existing SAFEs or notes
Series AA requires setting a valuation. Make sure it’s:
  • Justified by traction and metrics
  • Leaves room to grow into next round
  • Allows you to raise sufficient capital
  • Not so high that you can’t raise Series A
Before Series AA:
  • Convert all SAFEs and convertible notes
  • Buy out or convert any old option holders
  • Ensure all stock grants are properly documented
  • Have clean option pool ready
YC documents are already founder-friendly:
  • Don’t try to make them even lighter
  • Accept standard terms to close quickly
  • Save negotiating energy for larger rounds
  • Speed is more valuable than perfect terms
Even with standard docs, you need a lawyer:
  • Review all documents before signing
  • Customize schedules and exhibits
  • Ensure compliance with securities laws
  • File necessary documents with state

Resources & Downloads

Official Y Combinator Resources

Series AA Official Page

Main page with all document downloads

Term Sheet (Docracy)

Web version of term sheet

All Document Downloads

Alternative Formats

OpenLaw Template

Automated term sheet generation

Techstars Alternative

Similar seed-stage documents from Techstars
For incorporation before financing: For alternatives:

FAQ

Series AA is best if:
  • You’re raising 250K250K-2M from angels
  • You have clear traction and can set valuation
  • You’re past the SAFE stage
  • You want simple, founder-friendly terms
Consider alternatives if:
  • You’re pre-product or can’t justify valuation (use SAFE)
  • You’re raising from institutional VCs (use NVCA or Series Seed)
  • You’re raising under $250K (use SAFEs)
Yes, but:
  • Documents are meant to be starting templates
  • Customize financial terms (amount, valuation, etc.)
  • Generally avoid modifying standard legal provisions
  • Work with attorney to ensure modifications are appropriate
  • Over-customization defeats purpose of standardization
YC documents are for Delaware corporations:
  • Not suitable for non-US companies
  • Need to adapt significantly for other jurisdictions
  • Consider YC-style principles but local documents
  • Work with local counsel familiar with startup financings
Legal Disclaimer: These documents are templates and starting points. Always work with qualified legal counsel before executing any financing documents. The information here is educational and not legal advice.

Next Steps

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