July 22, 2026 · Investment Thesis, Underwriting
A thesis-driven investing framework you can actually enforce
By Emily Buckley, founder of SamCIO
Every fund has a thesis. It is usually a paragraph in the deck you show LPs: stage, sector, check size, some language about "differentiated" or "category-defining." The problem is not that the thesis is wrong. The problem is that most funds never turn it into something they check a deal against before they fall in love with it.
A thesis-driven investing framework is the difference between a thesis you can recite and a thesis you can enforce. Here is how to build the second kind.
Start with criteria, not adjectives
A usable thesis is a short list of concrete criteria: sector, stage, check size range, geography if it matters, and the two or three things about a business that make it a fit for your specific fund (a distribution advantage, a margin profile, a founder background you've seen work before). "Category-defining" is not a criterion. "B2B software selling into mid-market healthcare, $2-8M ARR, gross margin above 70%" is.
Write it down. Not in a deck for LPs, in a document the deal team actually opens when a new deal comes in.
Write the anti-thesis too
The more useful half of a thesis is what you explicitly do not do, and most funds skip it. An anti-thesis names the deals that look attractive but do not fit: maybe it is hardware with long sales cycles, maybe it is anything requiring a second fund to follow on meaningfully, maybe it is a sector you tried once and got burned on.
The anti-thesis matters because the deals that break discipline are rarely obvious misses. They are good companies that do not fit the mandate, pitched by founders you like, at a moment when the fund's pipeline is thin. Without a written anti-thesis, "this one's different" wins more often than it should.
Weight the criteria, don't just list them
A thesis with five criteria and no weighting lets every deal get a vague "mostly fits" and moves forward on momentum. A weighted framework forces the comparison: how much does thesis fit matter relative to team, market size, and traction, for this fund specifically? A seed fund betting on team and market long before traction exists should weight thesis fit and team heavily. A growth fund underwriting proven revenue should weight traction and terms more.
SamCIO's scoring model is built around four pillars, each independently weighted per fund: thesis fit, market opportunity, team execution, and traction and terms, with thesis fit defaulting to the largest single weight because it is the criterion earliest-stage funds most often skip under pressure. The weights are configurable because a growth fund and a seed fund should not be scoring deals the same way, but the discipline of having explicit weights, instead of a gut feel that shifts deal to deal, is the actual point.
Score every deal against it, even the ones you're excited about
The framework only works if it applies before conviction sets in, not after. The deals worth stress-testing against a written thesis are not the obvious passes, they are the ones the partner who took the first call is already excited about. That is exactly when an explicit, weighted thesis-fit score is most valuable: it either confirms the excitement is earned or it surfaces the gap the room was about to talk itself past.
This is also where the practice earns its keep across deals, not just within one. If every deal gets scored against the same weighted criteria, the fund can look back at a quarter of deals and ask which ones scored well but underperformed, and which ones scored poorly but the partner pushed through anyway. That comparison is only possible if the scoring was consistent and recorded, not reconstructed from memory after the fact.
Put it in the memo, not just the meeting
A thesis-driven framework that lives only in a partner's head at the IC meeting does not survive turnover, and it does not produce a record. The thesis fit section of the IC memo is where the framework becomes durable: state the criteria the deal matches, the criteria it misses, and whether anything touches the anti-thesis, in writing, attached to the deal permanently. Two years later, when a new partner asks why the fund passed on something that turned out well, the memo has the actual reasoning, not a reconstruction.
The failure mode to watch for
The most common way thesis discipline erodes is not a single bad decision, it is drift: criteria that quietly loosen deal by deal because the pipeline is thin this quarter, or because one partner's pet sector keeps getting exceptions. A written, weighted framework does not prevent a fund from ever making an exception. It makes the exception visible, which is usually enough to make it rare.
If you are building this from scratch, start with the criteria and the anti-thesis before touching the weights. Weights are easy to tune later. A thesis that was never written down cannot be tuned at all, because there is nothing to check the next deal against.
SamCIO scores every deal against your fund's own thesis weights automatically as part of the memo draft, so the check happens by default rather than depending on someone remembering to do it. You can see how the full scoring model works on the AI underwriting page.