Founding teams that worked well through the first year often struggle in the second. The change is not personal deterioration but the arrival of decisions the early stage never required.
Early work hides differences in judgement
At the beginning there is one obvious task: build something and find someone who wants it. Everyone does everything, and priorities are set by whatever is blocking progress today.
Disagreements in that period are about tactics, and tactics are settled quickly by evidence. Nobody has to reconcile a broader difference in what the company is for.
So a founding team can share a year of intense work without discovering that they want different things from the outcome.
Growth forces choices that reveal preferences
Once there is revenue, the questions change. Whether to pursue larger customers, whether to raise money, how fast to hire and what to stop doing all become live.
Each of these encodes a preference about risk, ambition and the kind of company the founders want to spend their next decade inside.
Those preferences were always present. They simply had no way to conflict while everyone was doing the same undifferentiated work.
Roles harden and comparisons begin
Specialisation arrives with the first hires. One founder ends up owning customers, another owns the product, and their days stop resembling each other.
Contribution then becomes harder to compare, and equity splits agreed when everyone did everything start to feel like a statement about relative value.
Resentment in these situations usually attaches to visible things such as titles or who speaks to investors, but it is generally about the sense that the original bargain has drifted.
The mechanisms that help are set up early
Clear decision rights matter more than consensus. Naming who decides in each area removes the need to relitigate authority during a disagreement about substance.
Vesting schedules and written founder agreements exist for the same reason, giving a structure that operates when goodwill is thin rather than when it is plentiful.
Teams that revisit the arrangement deliberately as the company changes tend to fare better than those who treat the founding agreement as settled, because the company being governed is no longer the one that was founded.
Outside pressure brings everything forward
A financing round, an acquisition approach or a poor quarter forces founders to state positions they had been able to leave ambiguous.
Investors ask directly who runs the company and what the plan is, and a team that has avoided settling that has to settle it under a deadline.
Disagreements that would otherwise have surfaced slowly therefore tend to arrive at once, which is why co-founder splits so often look abrupt from outside the company.