Co-Founder Conflict Glossary: 25 Terms Every Founding Team Should Know
Founders describe co-founder conflict in borrowed language — from couples work, from law, from venture — and the borrowed words are often where the misunderstanding starts. This glossary defines the twenty-five terms we use across our co-founder cluster, in a sentence or two each, with a pointer to where each one is covered in depth. Some are standard; the ones marked as ours are frameworks Aether Practice uses in co-founder sessions.
This article is part of our guide to co-founder conflict.
Short answer: the six terms that matter most
If you read nothing else: co-founder conflict is disagreement between founders that has stopped producing decisions. The contribution ledger is the private tally each founder keeps of who is carrying more. Deadlock is what happens when two founders with equal power disagree and have no agreed way to break the tie. Unspoken terms are the implicit agreement a founding team runs on and never writes down. Co-founder coaching is structured work on the partnership itself with all founders in the room. And a co-founder separation is the end of the founding partnership, which the company survives when the sequence is right.
Everything below elaborates on those.
The conflict itself
Co-founder conflict
Disagreement between founders that has stopped producing decisions. Disagreement itself is healthy and is what a founding pair is for; conflict in the problematic sense is when it ends in a truce that gets relitigated, moves out of the room into Slack or silence, or acquires a constituency. Noam Wasserman's research at Harvard Business School attributed roughly 65 percent of high-potential startup failures to conflict among founders. Complete guide.
The Six Patterns (Aether Practice)
The six recurring mechanisms behind most co-founder conflict: the contribution ledger, the 50/50 deadlock, role drift, divergent ambition, the avoided subject, and trust erosion by small increments. They are patterns rather than personalities, which is why they respond to changes in how a founding team operates rather than to one person trying harder. Complete guide.
Unspoken terms (Aether Practice)
The implicit agreement every founding team runs on and almost none writes down: how hard is hard enough, who decides when you disagree, what you are building toward, what would make either of you leave, and how you disagree in front of the team. Most co-founder conflict is two founders discovering, years in, that they signed different implicit contracts. The thirty questions that make them explicit.
The Repairability Check (Aether Practice)
Eight yes-or-no questions that distinguish a bad quarter from a broken partnership. Zero to two yeses is ordinary load; three to five is a pattern that will not resolve by itself; six or more means the partnership is running on avoidance and needs someone outside it in the room. The check.
Warning signs
The observable symptoms of the Six Patterns: reopened decisions, an avoided subject, arguments prepared in advance, important things routed through a third person, a team managing around the tension. Twelve, ranked.
The patterns
Contribution ledger
The private, running tally each founder keeps of who is carrying more. It is almost never spoken aloud because saying it sounds petty, so it is expressed sideways, and because it is private it is never corrected. Both founders usually believe they are carrying more, drawing on different evidence. Complete guide · When the ledger is about effort.
Role drift
The gap that opens when founders split responsibilities based on who they were at the start and never renegotiate as the company changes. It produces overlapping decision rights in some areas and gaps in others, and every collision in the overlap feels like an incursion.
Divergent ambition
Two founders wanting incompatible things from the company — a venture outcome versus a profitable company they own, or a sale at a number one finds insulting — which stays invisible while the near-term work looks identical and surfaces at a term sheet or acquisition offer. One of the Two Terminal Conditions. Separation.
The avoided subject
The one conversation a founding team is not having, usually equity, someone's performance, or whether one of them still wants to be here. Rational to avoid at first; the cost compounds, because everything else in the relationship has to navigate around it.
Trust erosion by small increments
Loss of trust without a betrayal: a commitment missed, a decision made without you, a version of events given to the team that was not quite how it happened. Each too small to raise; together they change how you listen. Distinct from a breach, which is a single large event, and much more repairable.
Decisions and structure
50/50 deadlock
The paralysis produced when two founders hold equal voting power, genuinely disagree, and have no agreed tiebreaker, so the disagreement waits until one of them gives in. A design flaw, not a character flaw. The deadlock article.
The Stamina Problem (Aether Practice)
The mechanism by which deadlock picks a winner: it does not stop decisions, it outsources them to whoever can tolerate more discomfort, so the same founder concedes every time and starts keeping a ledger while the other learns that persistence works. The deadlock article.
Domain ownership
The practice of giving each founder sole decision authority over defined areas — product, go-to-market, hiring, finance — such that the owner can make a call the other disagrees with and it sticks. The other founder gets full input and no veto. The strongest and most under-used fix for deadlock.
Tiebreaker
A person or rule, agreed in advance and in calm, that settles anything the founders deadlock on. A trusted operator, a board member both respect, a domain-owner rule, a rotating final word. Used rarely; a tiebreaker invoked monthly is a third founder.
The reversibility test
Classifying a decision before arguing about it. Reversible decisions go to whoever cares more, now; irreversible ones get the full process. Most founder deadlock is spent on reversible decisions treated as permanent.
Deadlock provision
The legal layer: a clause in a shareholders' or operating agreement specifying what happens when founders cannot agree — a casting vote, mediation, a buy-sell mechanism. The fire exit, not the operating tool.
Contribution and equity
Founder vesting
The arrangement under which founders earn their shares over time, typically four years with a one-year cliff, so that a founder who leaves early does not keep a large stake in a company they are not building. Adding it to an existing founding team is common and usually the easiest equity conversation available. Equity renegotiation.
The Four Readings (Aether Practice)
The four different things a co-founder who has stopped delivering may be: burned out (capacity gone, wants to recover), mismatched (working hard at a role the company has outgrown), disengaged (has stopped believing), or quietly departed (already gone, waiting for a date). They look identical from outside and need different responses. The article.
The Forecast Frame (Aether Practice)
The framing that lets co-founders reopen an equity split without it landing as an attack: the original split was a forecast made at the moment of maximum uncertainty, the forecast was wrong, and correcting it is a shared problem rather than a settled score. Equity renegotiation.
Top-up grant
An alternative to moving equity between founders: the company issues new shares to the founder who is under-weighted, diluting everyone equally. Small difference on a cap table, large difference in a relationship, because nobody is being taken from.
Getting help
Co-founder coaching
Structured sessions with all founders present, focused on the working partnership: how you decide, disagree, divide responsibility and repair. The practitioner's client is the partnership, not either founder and not the company. Operational rather than personal; not executive coaching, not mediation, and not therapy or clinical care, though its methods borrow from couples work. Sometimes called co-founder therapy. What it is and costs.
Co-founder mediation
A structured process run by a neutral third party toward a specific settlement — equity terms, departure terms — ending when there is an agreement both parties will sign. It concludes a dispute; it does not improve how the founders operate afterwards. Mediation, coaching or a lawyer.
Rehearsal
Practising a high-stakes conversation before having it, in a setting where the stakes are not real: in a co-founder session, or against a model built to hold a position rather than agree, such as AET01 Conflict. People who rehearse hold their position more clearly and concede less for the sake of ending the discomfort.
Executive coaching
One founder working with one coach on that founder's development as a leader. Changes the person, not the relationship; two founders each with an excellent coach can remain entirely stuck because the thing between them is not in either room.
Separation
The Two Terminal Conditions (Aether Practice)
The two situations in which a co-founder relationship is genuinely over: divergent ambition that no structure reconciles, and a specific, large breach of trust that neither founder can rebuild. Almost everything else, including a year of resentment, is repairable. Separation.
The Separation Sequence (Aether Practice)
The six steps, in a fixed order, that let a company survive a co-founder's departure: both founders accept it is over; agree the shape; agree the numbers; then bring in lawyers; then tell the board; then tell the team. Most damaging separations are the right decisions taken in the wrong sequence, usually with lawyers second. Separation.
FAQ: co-founder terms
What is co-founder coaching?
Structured sessions with all founders present, focused on how the founding team decides, disagrees, divides responsibility and repairs after conflict. The practitioner's client is the partnership. It is not executive coaching, not mediation, and not therapy or clinical care.
What is co-founder deadlock?
The paralysis that results when two founders with equal voting power disagree and have no agreed way to break the tie. It is a decision-rights problem, usually fixed with domain ownership and a named tiebreaker rather than a change to the equity split.
What is a contribution ledger?
The private running tally a founder keeps of who is carrying more in the company. It is rarely spoken aloud, so it is never corrected, and both founders in a partnership usually believe they are the one carrying more.
What is founder vesting?
An arrangement under which founders earn their shares over time, typically four years with a one-year cliff, so a founder who leaves early does not keep a large stake they did not finish earning. It can be added to existing founder shares and investors generally expect it.
What is the difference between co-founder coaching and co-founder therapy?
In practice none: "co-founder therapy" is what founders call coaching whose methods borrow from couples work. Clinical therapy is a separate, licensed activity with a different purpose. Co-founder coaching is work on a business partnership.
What is a co-founder prenup?
A colloquial name for a written agreement between founders about expectations, decision rights, commitment and what happens if the partnership ends, made while everyone is still friendly. Thirty questions it should answer.
Next step
If a term here named something you have been living inside without a word for it, that is usually the moment to say it out loud to your co-founder.
Aether Practice offers co-founder sessions for founding teams in San Francisco, New York City and Norway — both of you in the room, online, putting words to what the two of you have so far only assumed.
Keep reading in this cluster: The complete guide to co-founder conflict · Twelve warning signs · The 50/50 deadlock · Co-founder coaching in San Francisco and New York
Research and further reading
- Wasserman, N. (2012). The Founder's Dilemmas: Anticipating and Avoiding the Pitfalls That Can Sink a Startup. Princeton University Press. Where several of the cluster's terms about founder stability and early decisions originate.
- Hellmann, T. & Wasserman, N. (2017). The first deal: The division of founder equity in new ventures. Management Science, 63(8), 2647–2666. The study that turned the equal split from folk practice into a measured phenomenon.
- Christensen, A. & Heavey, C. L. (1990). Gender and social structure in the demand/withdraw pattern of marital conflict. Journal of Personality and Social Psychology, 59(1), 73–81. The original description of the pursue–withdraw pattern this glossary borrows from couples research.
- Jehn, K. A. (1995). A multimethod examination of the benefits and detriments of intragroup conflict. Administrative Science Quarterly, 40(2), 256–282. The task-versus-relationship distinction that separates disagreement that produces decisions from the kind that stalls a company.
- Shaikh, O., Chai, V., Gelfand, M., Yang, D. & Bernstein, M. S. (2024). Rehearsal: Simulating conflict to teach conflict resolution. Proceedings of the CHI Conference on Human Factors in Computing Systems. The Stanford study behind the rehearsal entry: people who practised against a simulated counterpart used fewer escalating moves in a later real conflict.
- Also read: Four conflict patterns couples repeat · AET01 Conflict · Co-founder coaching
Last updated: October 2026.
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