What is Simple Agreement for Future Equity?
Short answer: A simple agreement for future equity, or SAFE, is a financing contract that gives an investor rights to receive shares or a payment when specified events occur. It is not the shares themselves. In the widely used Y Combinator forms, it is also not a loan: it has no interest and no maturity date. A modified form or a local-law version can work differently, so the signed instrument matters more than the label.
A SAFE normally addresses an equity financing, a liquidity event such as a sale, and dissolution. A valuation cap sets a maximum company value used to calculate conversion shares. A discount instead reduces the price paid by new-money investors. Some forms use one feature, some use both, and an uncapped most-favoured-nation form may let the holder adopt more favourable terms issued later. A post-money cap generally measures SAFE ownership after the relevant SAFE money but before new cash in the priced round. That differs from older pre-money forms, where later SAFEs could change each holder's implied percentage. A pro rata right is usually separate and should not be assumed.
How it works
Build the calculation from the exact definitions of Company Capitalization, Safe Price, Standard Preferred Stock and Safe Preferred Stock. For a cap-only post-money SAFE, an initial ownership estimate is purchase amount divided by post-money cap. At conversion, compare the safe price derived from the cap with the financing price and use the contractual outcome. Then add the priced-round shares and any option-pool increase. Also model sale and dissolution outcomes, including the SAFE's priority relative to shares and creditors. Maintain a schedule for every SAFE because different caps, discounts, side letters and amendments cannot be safely combined into one average term.
Initial post-money-cap ownership estimate = SAFE purchase amount / post-money valuation cap
Example
A company has 8,000,000 capitalization shares and issues two cap-only post-money SAFEs: 600,000 at a 6,000,000 cap and 400,000 at an 8,000,000 cap. Their ownership before new money in the priced round is 10% and 5%, respectively. Because the two SAFEs together represent 15%, post-SAFE Company Capitalization is 8,000,000 / 85% = 9,411,765 shares, subject to the executed definitions and rounding. The first SAFE receives about 941,176 shares and the second about 470,588. The priced round then issues 2,000,000 new shares at 1.20 for 2,400,000 of new cash. Before an option-pool change, total shares become about 11,411,765. The SAFE holders then own about 8.25% and 4.12%, showing how priced-round shares dilute their pre-round 10% and 5% interests.
Why it matters
A SAFE can close earlier and with fewer negotiated provisions than a priced preferred-share round, which can help fund a company while milestones are still developing. The board should nevertheless compare the implied ownership sold, future option-pool needs, pro rata commitments, conversion scenarios and liquidity priority with a convertible note or priced round. Investors should test whether the cap or discount is likely to drive conversion and whether information or participation rights sit outside the SAFE. The analysis belongs in the fully diluted cap table before each issuance, not only when a later round is imminent.
SAFE treatment is document-specific and jurisdiction-specific. The Y Combinator forms are designed for identified jurisdictions and explicitly recommend local legal review. Corporate approvals, securities-law exemptions, financial-statement classification, tax treatment and foreign-investment rules may differ. A SAFE may remain outstanding for an extended period if no triggering event occurs, and a liquidity payment can be limited by available proceeds and senior claims. Do not call every future-equity contract non-debt or assume a template is unmodified. Counsel should compare the execution copy with the published form, review side letters and confirm how the instrument ranks under company and insolvency law.