A thesis that admits everything is useless and one that admits nothing leaves you idle. The right width depends on how many opportunities you see and how much capital you need to deploy.
10 min read · Level 2
I think most investors set thesis width by taste and then discover the consequences a year later, when they are either drowning or idle. Doing the arithmetic first - opportunities needed, opportunities produced - turns a stylistic choice into an operational one, and it makes the later temptation to widen much easier to resist because you can see what it would cost you in attention.
Thesis width is a practical constraint, not a philosophical one. Three widths for the same investor:
Thesis Opportunities per year that fit "Software for small businesses" around 120 "Vertical software bought by the daily operator" around 30 "Scheduling software for dental practices" around 3
The first is too wide to reject anything and leaves the investor doing full diligence constantly. The third is precise but may not produce enough opportunities to build a portfolio.
The test is arithmetic. If you intend to make six investments a year and convert roughly one in five of the opportunities you investigate seriously, you need about 30 that fit your thesis annually. A thesis producing three is too narrow for that plan; one producing 120 is wider than you can process.
Width should also match where you actually know something. A thesis broad enough to include markets you cannot judge has stopped being a thesis and become a description of the whole market.
Width can change deliberately. Many investors start narrow, learn, and widen into adjacent areas where their knowledge transfers - keeping the widening explicit and dated rather than letting it drift.
Because the practical failure of a thesis is usually that it does not bind. A wide thesis lets every attractive opportunity through, which returns you to judging each one from scratch.
The opposite failure is less common but real: an investor with a precise thesis and no deal flow, waiting years for something to fit while capital sits idle.
Educational, not personalised financial advice. Nothing in the Investor Academy is a recommendation to buy, sell or hold anything — what is right for you depends on your own circumstances and the rules where you live.
An investor recalibrating. They planned eight investments a year and found their thesis admitted about 150 opportunities annually, more than they could screen properly.
Change Effect Added a stage constraint: pre-Series A only 150 down to about 70 Added a buyer constraint: operator-led sales 70 down to about 35 Kept geography open unchanged
At 35 opportunities a year with their conversion rate, eight investments was achievable and each received proper work. They dated the change and recorded the reasoning, so a future widening would be visible as a decision rather than drift.
Choosing thesis width by how it sounds rather than by how many opportunities it produces relative to the number of investments you intend to make.
Review a year of opportunities and count how many would have fitted.
Divide intended investments by your conversion rate to find how many fitting opportunities you need.
Adjust stage, buyer, geography or business model, and re-count.
Record when and why the width changed, so drift stays visible.
When setting a thesis for the first time, or when you are either overwhelmed by opportunities or idle for long periods.
Do not widen a thesis because you have capital to deploy and nothing fits. That is the moment it is protecting you most.
Investors who raise substantially larger funds frequently broaden their stated focus to deploy the capital, moving into adjacent sectors or later stages. Industry commentary often notes this as a source of strategy drift, since the larger fund must find more opportunities than the original focus produced.
When capital grows faster than the opportunity set, something has to give. Decide deliberately whether it is the thesis or the deployment plan.
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