Based on Y Combinator's Standard Agreements

The SAFE Note
Explained

Simple Agreement for Future Equity - The fastest way for startups to raise money without the complexity of traditional fundraising.

2013
First Introduced
1
Document Needed
~0
Legal Fees
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The Basics
What is a SAFE?
A SAFE is not a loan. It's not stock. It's a promise that an investor's money will convert into shares in the future when a specific event happens.
💰

Investor Gives Money Now

An investor pays a specific amount (the "Purchase Amount") to your startup. This money goes directly to the company to fund operations.

📄

Company Gives a Promise

In return, the company promises that the investor will get shares in the future - when a qualifying event happens (like a Series A round).

📈

Shares Come Later

When the company raises a priced round (Equity Financing), the SAFE automatically converts into preferred stock at a price favorable to the early investor.

Think of it like this: A SAFE is like a gift card for future stock. You pay now, and when the company sets a price for its stock (in a future funding round), your gift card automatically redeems for shares - usually at a better price than what new investors pay.

Why Use a SAFE Instead of Traditional Methods?
SAFEs replaced convertible notes as the standard for early-stage fundraising. Here's why.

⚡ Speed

Close with each investor as soon as they're ready. No need to coordinate all investors for a single closing date. An investor can sign and wire money the same day.

📝 Simplicity

It's a single, short document. Only one thing to negotiate: the valuation cap. No interest rates, no maturity dates, no complex clauses.

💰 Low Cost

Minimal legal fees because it's a standardized form. Most founders can use it with little to no lawyer involvement for the document itself.

🕐 No Expiration

Unlike convertible notes, a SAFE has no maturity date. There's no deadline pressure to raise another round or repay the investor.

🔥 Not a Loan

A SAFE is an equity instrument, not debt. There are no interest payments, no accruing obligations, and no risk of default.

📊 Transparent Ownership

With the post-money SAFE, both founders and investors can instantly calculate exactly what percentage of the company has been sold.

Comparison
SAFE vs. Convertible Note vs. Priced Round
Understanding the differences helps you pick the right instrument for your situation.
Feature SAFE (Post-Money) Convertible Note Priced Round (Series A)
Document Complexity Simple - 1 document Moderate - multiple docs Complex - many docs
Legal Costs Minimal (~$0-2K) Low-Moderate ($2-5K) High ($10-40K+)
Speed to Close Days 1-2 Weeks Weeks to Months
Is It Debt? No (equity) Yes (debt) No (equity)
Interest Rate None Yes (typically 2-8%) None
Maturity Date None Yes (12-24 months) Not applicable
Ownership Clarity Immediately clear Uncertain until conversion Fully defined
Negotiation Points 1 (valuation cap) 3-5 terms Many terms
Best For Pre-seed / Seed Bridge rounds Series A and later
Three Types of Post-Money SAFEs
There are three standard SAFE templates. Each serves a different purpose.

Valuation Cap SAFE

The standard and most widely used version. The Valuation Cap sets a maximum company value at which the investor's money converts into shares.

How it protects the investor: If the company's valuation grows massively before the next round, the SAFE investor still converts at the capped (lower) valuation, getting more shares for their money.

Example: You invest $500K with a $5M post-money cap. The company later raises a Series A at a $50M valuation. Your SAFE converts as if the company was worth $5M, giving you 10% ownership (before Series A dilution) instead of 1%.

Ownership = Investment / Post-Money Valuation Cap

$500K / $5M = 10%

Key Point: Post-money cap includes ALL the SAFE money. So if you raise $1M total on SAFEs with a $5M cap, investors own 20% combined ($1M / $5M).

Discount Only SAFE

Instead of a cap, this SAFE gives the investor a percentage discount on the price paid by Series A investors.

The Discount Rate: Expressed as a percentage of the Series A price. A "20% discount" means the SAFE investor pays 80% of what new investors pay (Discount Rate = 80%).

Example: Series A investors pay $2.00 per share. Your 20% discount means you pay $1.60 per share. A $100K investment gets you 62,500 shares instead of 50,000.

Your Price = Series A Price × Discount Rate

$2.00 × 80% = $1.60/share

MFN (Most Favored Nation) SAFE

No cap. No discount. But if the company later issues SAFEs with better terms (like a valuation cap or discount), this investor can adopt those better terms.

Think of it as: "I'll match whatever deal the next investor gets." It's a safety net for very early investors when terms are hard to establish.

Important: The MFN is a one-time amendment right. You adopt the full terms of the later SAFE - you can't cherry-pick individual provisions. If never triggered, the SAFE converts at the same price as new investors (no special treatment).

Best used when: The company is so early that setting a valuation cap is impossible. Common for the very first check into a brand-new idea.

The Mechanics
How a SAFE Actually Works
From signing to conversion - here's the journey of a SAFE.

👤 Investor

Wires $500K to the company

📄 SAFE Signed

$5M Post-Money Cap

🚀 Company Grows

Builds product, hires team

💸 Series A

Raises at $20M pre-money

🔔 Auto-Conversion

SAFE becomes preferred shares

The Conversion Math

When a SAFE converts in an Equity Financing, the investor gets the greater of two calculations:

Option A: Using the Valuation Cap

Shares = Purchase Amount / Safe Price
Where Safe Price = Post-Money Cap / Company Capitalization

This gives the investor Safe Preferred Stock at a lower price per share.

Option B: Using the Series A Price

Shares = Purchase Amount / Series A Price Per Share

The investor gets Standard Preferred Stock at the same price as new investors.

The investor automatically gets whichever option results in more shares. Usually Option A wins (the valuation cap), which is why the cap is the most important term.

What's Included in "Company Capitalization"?

This is the denominator used to calculate how many shares the SAFE converts into:

All shares of stock issued and outstanding
All outstanding stock options
Promised but ungranted options
Existing unissued option pool
All other SAFEs & convertible securities
New option pool increase from Series A

Why this matters: SAFEs don't dilute each other - they all come out of the same post-money cap. But they ARE diluted by the Series A new money and its option pool increase, just like everyone else.

SAFE Ownership Calculator
Play with the numbers to see how different terms affect ownership.
10%
Your Ownership (Post-SAFE)
20%
Total SAFE Ownership
80%
Founder Ownership (Post-SAFE)
--
Your Ownership (Post-Series A)
Possible Outcomes
What Happens to Your SAFE?
A SAFE converts or pays out depending on what happens to the company.
📈

Equity Financing (Series A)

The SAFE automatically converts into preferred stock. The investor gets shares based on the valuation cap vs. the round price (whichever gives more shares). This is the most common outcome.

🏠

Acquisition (Liquidity Event)

The investor gets the greater of: (1) their money back (Purchase Amount), or (2) the share of sale proceeds they'd get if the SAFE converted to stock. SAFE holders rank on par with preferred stockholders.

🌎

IPO / Direct Listing

Also a Liquidity Event. The SAFE converts to common stock, and the investor can eventually sell on the public market. Same payout logic as an acquisition.

🚫

Company Shuts Down

The investor is entitled to get their Purchase Amount back - but only after creditors and debt holders are paid. In practice, if a startup shuts down, there's usually little money left.

🕐

Nothing Happens

The SAFE just sits there. It never expires. The company keeps operating without raising a priced round. The investor's money is at work, but there's no conversion or payout.

Priority Order in Liquidation: Creditors & Debt → SAFE Holders & Preferred Stock (same level) → Common Stockholders. SAFEs are junior to debt but senior to common stock.

The SAFE Lifecycle for Founders
From fundraising to conversion, here's what you need to do at each stage.

1. Board Approval

Your board of directors must formally approve the issuance of SAFEs before you send any out. This is a legal requirement - don't skip it.

2. Set Your Target Raise & Valuation Cap

Know how much you want to raise and what ownership you're willing to sell. Ownership = Total Raise / Post-Money Cap. Targeting $1M raise and 15% sold? Your cap is ~$6.7M.

3. Sign SAFEs & Collect Wire Transfers

Close with each investor individually. They sign the SAFE, wire the money, done. You can close multiple investors over weeks or months.

4. Maintain Your Cap Table

Track all SAFEs carefully. Record each investor, their purchase amount, and the valuation cap. This is critical for when you raise your next round.

5. Build Your Company

Use the money to build your product, grow your team, and hit milestones. The SAFEs sit quietly in the background until a triggering event.

6. Raise a Priced Round (Series A)

When you raise your next round, all SAFEs automatically convert into preferred stock. The conversion happens at the initial closing - no action needed from SAFE holders.

Optional Add-On
The Pro Rata Side Letter
An optional companion document that gives SAFE investors the right to invest more in your next round.

What Is It?

A Pro Rata Side Letter gives a SAFE investor the right to invest in your Equity Financing (e.g., Series A) to maintain their ownership percentage.

Example: An investor owns 10% via their SAFE. When you raise a $5M Series A, they have the right to invest up to $500K (10% of the round) in the Series A to maintain their 10% stake.

Founder Warning: Be careful about giving pro rata rights to too many investors. When the Series A comes, you need to make room for new investors + existing investors with pro rata rights. Too many pro rata commitments = more dilution than expected.

Strategies for Giving Pro Rata Rights

Minimum Investment Threshold

Only give pro rata rights to investors who invest above a certain amount (e.g., $250K+). This is simple and limits how many investors you need to manage at Series A time.

Give to Everyone

Simplest approach, least negotiation. But may mean more dilution at Series A if everyone exercises. Trade-off: easy now, potentially complex later.

Target a Pro Rata Budget

Estimate how much extra ownership you'll sell at Series A from pro rata rights, and only allocate that much. Requires planning but gives the best control.

Real Numbers: From SAFE to Series A
Let's walk through a complete example with actual numbers.

SAFE Round

Investor A $200K @ $4M cap = 5%
Investor B $800K @ $8M cap = 10%
Total Raised $1,000,000
Total Sold 15% minimum

Cap Table (Post-SAFE, Pre-Series A)

Founders ~81%
Options (Outstanding) ~7.2%
Unissued Pool ~1.8%
Investor A (SAFE) 5%
Investor B (SAFE) 10%
Important Warning
Watch Your Dilution
The most common mistake founders make with SAFEs.

You cannot raise more than the Post-Money Valuation Cap!

If your cap is $5M, and you raise $5M in SAFEs, investors own 100% and founders own 0%. Always raise significantly less than the cap.

Amount Raised SAFE Ownership Founder Ownership
$500K $500K / $5M = 10% 90%
$1M $1M / $5M = 20% 80%
$2.5M $2.5M / $5M = 50% 50%
$5M $5M / $5M = 100% 0%

Founder Tips to Manage Dilution

Know Your Target Range

Before issuing SAFEs, decide: "We want to raise $X and sell no more than Y%." Then set your cap accordingly: Cap = Raise / Target %.

Plan for Total Dilution

Don't just think about the SAFE round. Model out the Series A too. SAFE dilution + Series A dilution + option pool can easily total 50%+ combined.

Be Careful with Multiple Caps

If you issue SAFEs at different caps, add up the ownership from each: $500K at $5.5M cap (~9%) + $500K at $8.3M cap (~6%) = 15% total.

Budget Pro Rata Rights

Pro rata commitments add extra dilution at Series A. Factor this in when planning how much total dilution you'll accept.

Frequently Asked Questions
Quick answers to the questions founders and investors ask most.
Is a SAFE the same as giving away stock right now?
No. A SAFE is a promise of future shares, not current stock. The investor doesn't become a stockholder until the SAFE converts (typically at the next priced round). Until then, they have no voting rights and no official ownership - just a contractual right to future shares.
Can I modify the standard SAFE template?
The SAFE template includes a statement that neither party has modified the form. If you do modify it, remove that statement. The whole point of a standardized document is that neither side needs to pay lawyers to review changes. If you make custom changes, you lose that benefit, and the other party will want their lawyer to review everything line by line.
Can I mix convertible notes with SAFEs?
It's generally not advisable. Convertible notes are treated as debt and have higher priority than SAFEs in a liquidation. This creates complexity and potential conflicts between investors. If you already have convertible notes, either continue with notes or work with existing noteholders to convert them into SAFEs.
Does the investor get a board seat with a SAFE?
No. SAFEs don't come with governance rights like board seats, voting rights, or information rights. These are typically negotiated in priced rounds (Series A). This is one reason some larger investors may prefer a priced round over a SAFE.
Can the investor sell or transfer their SAFE?
Not without the company's consent. The SAFE includes a transfer restriction. An investor can transfer to affiliates or family members without consent, but selling to a different investor requires company approval. This gives founders control over their investor base.
What if my Series A valuation is LOWER than the SAFE's valuation cap?
The SAFE investor gets shares at the Series A price (the lower price), which gives them MORE shares than the cap would imply. The cap is exactly that - a cap, not a floor. The investor always gets the better deal between the cap price and the actual round price.
How is the SAFE treated for tax purposes?
Y Combinator intends the SAFE to be treated as an equity security (specifically, similar to common stock) for US federal and state income tax purposes. However, tax treatment is complex and fact-specific - consult a tax advisor for your specific situation.
What if the company pays dividends while a SAFE is outstanding?
If the company pays a cash dividend to common stockholders while SAFEs are outstanding, SAFE holders are entitled to receive a proportional dividend based on their as-converted ownership. This protects investors if the company becomes profitable but never triggers a traditional conversion event.
Can a SAFE be amended after signing?
Yes. It requires written consent from either (1) the company and the individual investor, or (2) the company and a majority-in-interest of all SAFEs with the same terms. However, an investor's Purchase Amount can never be changed without that specific investor's individual consent.
Action Items
Founder's SAFE Checklist
Everything you need to do before, during, and after issuing SAFEs.

Before Issuing SAFEs

Get board approval

Formal board consent (meeting or written) is legally required

Set your fundraising target and cap

Cap = Total Raise / Target Ownership %

Decide on pro rata strategy

Who gets pro rata rights? Everyone? Only large investors?

Model total dilution

SAFEs + future Series A + option pool = total founder dilution

After Issuing SAFEs

Keep a clean cap table

Record every SAFE with investor name, amount, cap, and date

Track total ownership sold

Sum of all (investment / cap) across all SAFEs

Grant promised options promptly

Clear your option backlog before signing a Series A term sheet

Don't modify the template

Use the standard YC form as-is. Custom changes cost time & money.