Decision Cluster · Co-Founder Equity

AI for Co-Founder Equity Split Decisions

The equity-split conversation breaks more co-founder relationships than any other. Put it to a board of named experts first — and have a structured conversation instead of a fragile one.

Start free See how it works

In short

AI doesn't replace the conversation — it makes you more prepared for it. The panel surfaces the structural questions you both need to answer (vesting, decision rights, buyout terms) so the conversation is about facts, not vibes. Use it before the conversation, not instead of it.

Last reviewed October 1, 2026

An example

One ask, start to finish.
What comes back is a memo.

How a board takes a call like this: her read, who sits, what they ask first, then the call — with how sure they are, who disagreed and the first step.

Co-Founder Equity

Example · Board of 3

I started the company 6 months ago — should I split equally with a new co-founder?

Chief of staff

This one needs a board: The Investor, The Lawyer and The Empath. The Investor thinks like a board, an LP, and a downstream acquirer at once. Each researches alone first, then they react to one another — and on a decision, two of them take opposed sides.

The InvestorVC Partner
The LawyerLegal Protector
The EmpathPeople Advocate

Asked first

Are you after the biggest outcome, or the most certain one?

The biggestThe most certainNot sure

The board’s call

Split 55/45 in favor of the original founder.

50/50 splits feel fair but cause more deadlocks than asymmetric ones. 55/45 with vesting gives weight to the original effort without creating resentment.

Confidence70 · Moderate

The Empath disagreed

“Avoid handshake agreements — papers always, with a lawyer, this quarter”

First step Add a written role-and-deliverable doc.this week

Board of 3 · up to 135 credits on the card · an example, not a recorded run

Other asks people bring here

Several asks in one message become several rooms, each with its expert and its own price on the card. Keep or drop any, then convene them together.

Two co-founders, one is CEO and one is CTO. Equal split or 55/45? — The Lawyer, up to 85 credits
Three co-founders, very different contributions so far — how do we split? — The Empath, up to 85 credits
Should we use a dynamic-equity tool, or a static split with vesting? — The CEO, up to 85 credits

What you get

What she handles.
On this kind of call.

Multi-factor split

The board weighs contribution timeline, opportunity cost, capital risk, role weight, and post-funding dilution — not just "we're equal partners."

Vesting architecture

The Lawyer and Investor argue vesting cliffs, acceleration triggers, and what happens if a co-founder leaves at month 8 vs month 36.

Relationship-preservation read

The Empath flags split structures that feel fair on paper but resent silently.

Future-proofing the cap table

The Investor models what the split looks like after Series A and B — most founder fights are about dilution, not the original split.

Why SynthBoard

Why SynthBoard for this.
Not one voice. A board.

Beyond the split percentage

The board weighs vesting, role definition, decision rights, and exit mechanics — the parts that actually determine whether the relationship survives.

Names what nobody says

The Empath surfaces what each co-founder is privately worried about — the conversation you both need but neither will start.

Structured memo for the lawyer

Every board ends in a memo you can hand to your startup attorney as the basis for the founder agreement.

Long-horizon framing

The Investor models the split after multiple funding rounds — most founder fights happen later, not at incorporation.

Who sits

The experts for this call.
Each one holds a position.

Your Chief of Staff proposes who sits for the call, and every board is built with someone whose job is to argue against the obvious answer. Name an expert and they take a seat; tell her who you want on your board and they sit by default. How many seats a board has depends on your plan.

VC Partner

The Investor

I’m not asking if it can work. I’m asking if it can get big, and what it’s worth if it can’t.

The Investor VC Partner

Best on: Raising, valuation, selling, or a job offer against your own company.
Won’t let you: Mistake a good small business for a fundable one, or the reverse.

Try asking The Investor

Start with

The InvestorOpen on every plan, Free included

Pick an expert

Hover, tap or tab throughSwipe, then tap one

GPT
Claude
Gemini
Grok

Seats are spread across model families: GPT, Claude, Gemini, Grok and more.

Questions

Fair questions.
Straight answers.

What people ask before they bring this call to a board.

Is AI the right tool for such a sensitive conversation?

Can we both run this together?

Yes — and you should. Each of you runs a board on your own first, then you share the memos and compare. The discrepancies are usually where the conversation needs to happen.

What's a fair split when contributions are very different?

The panel will propose splits based on the inputs you describe — capital, time, IP, network, opportunity cost. There's no single "fair" answer, but a structured argument beats a vibes-based negotiation.

Should we use a dynamic equity model like Slicing Pie?

The board will weigh it — dynamic models work for some teams and not others. The trade-off is fairness-as-you-go versus simplicity at fundraise. The Lawyer and Investor will weigh both.

Does this replace a startup lawyer?

No — it sharpens the conversation you take into the lawyer's office. A lawyer charges for the paperwork; a board works out the structure before the paperwork. They're complementary.

Is this confidential?

Yes. Your decisions are private to your account and never used to train models. Think through the most sensitive co-founder questions without exposure.

SynthBoard (synthboard.ai) is one place for your business, your life, and every hard call. Your Chief of Staff keeps what you tell her on file, and 24 named experts on different AI models take the calls — one expert for a consult, a board with opposed seats for the hard ones — and hand back a memo with the call, the dissent and the first move. How it works.