How accelerator SAFEs work: caps, discounts, and MFN clauses

When an accelerator invests cash, it often does so through a SAFEiA Simple Agreement for Future Equity: money now that converts into shares later, not a loan. rather than buying shares outright. A SAFE is not a loan and not stock yet. It is a promise that the money converts into shares later, usually at your next priced round. What you actually give up depends on three small terms buried in the document: the cap, the discount, and sometimes an MFN clause. This guide explains each, then walks a worked example so the mechanics are concrete.

The cap and the discount

Two levers decide how many shares a SAFE turns into.

• The valuation capiThe highest company value used to price a SAFE when it converts, which protects the investor. sets the highest company value used to price the conversion. If your next round values the company above the cap, the SAFE converts as if the value were the cap. A lower cap means the investor gets more shares for the same money, which is more dilutive for you.
• The discountiA percentage off the next round's share price, given to earlier SAFE investors. gives the SAFE a percentage off the new round's share price. A 20 percent discount means the SAFE pays 80 percent of what new investors pay per share.

When a SAFE has both, it almost always converts at whichever gives the investor more shares. On a post-moneyiThe company's value right after an investment lands, equal to pre-money plus the amount invested. SAFE, the investor's final ownership percentage is fixed at signing, which makes your dilutioniThe drop in your ownership percentage when the company issues new shares. easier to predict.

The MFN clause, and why it matters later

An MFN clauseiMost Favored Nation: lets an earlier investor upgrade to the best terms you later give anyone else. lets an early investor adopt the best terms you later give anyone else on a similar instrument. Accelerators sometimes take an uncapped SAFE with an MFN, which sounds founder-friendly at signing because there is no cap today. The catch is that if you later issue a SAFE with a low cap, the MFN holder can reach back and take that cap too.

The numbers below are round hypotheticals.

Setup:

• An accelerator invests 50,000 dollars on an uncapped SAFE that includes an MFN clause.
• Months later you raise a bridge on SAFEs with a 5,000,000 dollar post-money cap.
• The MFN lets the accelerator swap its uncapped SAFE for that 5,000,000 dollar cap.
• Finally you close a priced round at a 10,000,000 dollar post-money valuation.

Conversion, without the MFN:

• Uncapped, so it converts at the round price. Ownership is 50,000 divided by 10,000,000, which is 0.5 percent.

Conversion, with the MFN adopting the 5,000,000 cap:

• It converts at the cap. Ownership is 50,000 divided by 5,000,000, which is 1.0 percent.

The MFN doubled the accelerator's stake, from 0.5 percent to 1.0 percent, and doubled the dilution you take from that check. Nothing changed about how much money they put in. One clause, triggered by a later financing you had not done yet, moved the outcome.

What to actually check before you sign

• Find the cap and the discount, and compute your ownership at a realistic next-round valuation. Do the arithmetic, do not eyeball it.
• Look for an MFN clause. If it is there, remember that any low cap you grant later can flow back to it.
• Ask whether the SAFE is pre-money or post-money. Post-money fixes the investor's percentage and is more predictable for you.
• Check for pro rataiThe right to invest again later to keep your ownership percentage from shrinking. rights, which let the investor buy more later to hold their percentage.

Here are two programs that invest cash, so you can see how each presents its own terms:

FAQ

Is a SAFE better or worse than a priced round for me?

Neither by default. A SAFE is faster and cheaper to sign, but it defers the dilution math to conversion, so it is easy to give up more than you expected if you do not model the cap.

If my SAFE is uncapped, am I safe from dilution?

Not necessarily. An uncapped SAFE with an MFN can pick up a cap you grant later, as the worked example shows. Uncapped today does not mean uncapped forever.

Does a lower cap ever help the founder?

A lower cap always favors the investor on conversion. Founders accept lower caps to close faster or to reward early risk, not because the cap itself helps them.

This is general education, not legal or investment advice. Read the actual documents and talk to a lawyer before you sign.