If you’ve raised a pre-seed or seed round in the past few years, you likely did it through a SAFE (Simple Agreement for Future Equity). And if the early investor pushed back on your valuation cap, or you didn’t want to set one yet, you may also have agreed to a “Most Favored Nation” clause, usually called an MFN.
An MFN clause looks harmless. In plain terms, it promises the investor that if you later give someone else a better deal, the investor gets those better terms as well. Sounds fair, and few founders object to fairness. But in practice, an MFN can limit how you structure later rounds, complicate your cap table and cause friction with investors at exactly the wrong time.
This post covers how MFN clauses work in SAFEs, where the risks are, and what founders and investors should think about before including it.
What an MFN Clause Actually Does
The standard Y Combinator post-money SAFE comes in several versions. One version has no valuation cap and no discount, and relies instead only on an MFN provision. Under that version, if the company later issues other convertible securities (such as more SAFEs or convertible notes) before its priced equity round, and those securities have terms the MFN holder considers more favorable, the company must tell the holder and the holder can then choose to amend its SAFE to match those better terms.
Founders tend to reach for MFN SAFEs when very early money comes in from friends, family, or an angel before anyone has a real sense of valuation. They also use them to “hold the spot” for an investor without locking in economics too soon, or to reassure a strategic or anchor investor that it won’t be undercut by later investors in the same pre-priced round.
The pitch is appealing: “We’ll figure out the terms later, and you’ll never be worse off than anyone who comes after you.” The trouble lies in “figure out later.”
Setting Terms Now for Deals You Haven’t Negotiated Yet
The biggest risk is that an MFN turns every later convertible deal into a negotiation with more than one party. Say you give an angel an MFN SAFE. Six months later, a lead investor offers you a SAFE with a $10 million post-money cap. The angel can now take the $10 million cap.
That may be fine. But suppose market conditions have tightened and your next SAFE investor gets a lower cap, a discount, or a side letter with pro rata or information rights. Depending on how the MFN is drafted, each of those better terms may flow back to your earliest investors. Terms you agreed to under pressure, possibly to close one important investment, can quietly become terms for a much bigger group.
In other words, an MFN doesn’t just affect the investor who holds it. It changes how much it really costs you to agree to anything in later convertible rounds.
The Question of What Counts as “More Favorable”
Is a lower valuation cap with no discount “better” than a higher cap with a 20% discount? It depends on the price in the eventual equity round, which nobody knows when the MFN is triggered.
The standard SAFE MFN handles this by generally letting the holder decide whether it wants the later terms. That approach gives the investor wide discretion. Custom or heavily negotiated MFN clauses, however, are often less clear. We regularly see disputes over whether side letters granting pro rata rights, board observer seats, major investor status, or information rights count as “terms” that trigger the MFN. The standard MFN-only SAFE uses a take-it-or leave-it approach; either the MFN holder opts for the later terms, in which case the company is obligated to amend and restate the SAFE to be identical to the later instrument, or he doesn’t. But sometimes parties modify the standard MFN so that the holder may cherry-pick individual terms from different later instruments. Convertible notes add another wrinkle, because their interest and maturity features make a clean comparison to SAFEs difficult. And it’s not always clear whether securities issued to strategic partners, service providers, or under commercial arrangements fall within the MFN at all.
Moreover, vague drafting here doesn’t just create legal risk. It also creates relationship risk with the very investors who backed you first.
Notice Obligations that are Easy to Miss
MFN provisions usually require the company to notify MFN holders when it issues later convertible securities, and often to provide copies of the relevant documents. Busy management teams, especially those raising on a rolling basis, can easily forget this step.
Missing a notice obligation isn’t necessarily fatal, but it can hand investors an argument that they’re entitled to better terms retroactively. It can also create diligence headaches when a Series A lead investor’s counsel reviews your cap table and finds unresolved MFN rights, and it can erode trust with early investors who feel they were left out of the loop. A simple safeguard is to keep a tracker of every MFN you’ve granted, what it covers, and when and how notice must be given. Update it every time you issue a new SAFE or note.
Cap Table Uncertainty Heading Into Your Priced Round
MFN SAFEs can make your cap table harder to model. Until the MFN rights are resolved, you and your future investors may not know exactly which cap or discount applies to a given SAFE. If several MFN holders are waiting to see which later deal is “best,” conversion math can become a moving target.
Series A investors want clarity. Heading into a priced round with a stack of unresolved MFNs can mean extra legal fees, longer diligence and, in some cases, pressure to clean things up through amendments or consents before closing.
Signaling and Negotiating Leverage
An MFN can also affect how later investors see your round. Sophisticated investors will ask whether earlier investors hold MFN rights. If they do, the new investor knows that any concession it gets, e.g., a lower cap or special rights, will go to other investors too. That can make you less flexible in negotiations and, in some cases, can make later investors reluctant to ask for or accept terms that would trigger the MFN.
Sometimes the reverse happens, and founders use the MFN as a shield: “We can’t give you that, because it would flow to everyone.” That can be a legitimate negotiating tool, but only if you understand the clause’s scope well enough to use it credibly.
A Word for Investors
MFNs aren’t risk-free for investors either. An MFN-only SAFE with no cap and no discount offers real protection only if later convertible securities are actually issued before the priced round. If the company goes straight from your MFN SAFE to a priced equity round, the MFN may never apply, and you may end up converting on terms with no built-in economic benefit for investing early. Investors should also think about whether side letter rights matter to them, and whether the MFN as drafted actually captures those rights.
Using MFNs Wisely
None of this of course means MFNs are inherently bad. They can be a genuinely useful tool for getting early capital in the door, but using them well takes some discipline. Where possible, stick with widely used forms like the post-money SAFE; investors and their counsel know them well, which reduces surprises and the risk of disputes. If you do negotiate a custom MFN, spell out which securities trigger it, whether side letters are included, and whether the holder must take a whole package of terms rather than picking favorites.
It is also worth considering a sunset. An MFN that expires on a set date, or once a certain amount has been raised, is far easier to manage than an open-ended one. Treat notice obligations like any other contractual compliance item, and before granting an MFN at all, take a moment to model the downside by asking what happens if your next SAFE round comes in on worse terms than you expect. Finally, resolve outstanding MFN rights well before your priced round so they don’t slow down your Series A.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
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