We Re-Buy the Portfolio Every Day
Owning something is a decision you are making this morning, not one you made two years ago.
We own nothing by default. Every position is re-underwritten at today’s price against today’s evidence, and if we would not buy it today we do not own it today. That is a procedure, not a slogan.
The alternative is the most expensive habit in the business. Once you have paid forty dollars for something, forty becomes the reference point: twenty-eight looks cheap, fifty-two looks like a win, and neither number has anything to do with what the asset is worth. The market does not know your basis and will never price around it.
So we ask the uncomfortable version of the question. Bad news arrives and the position is down fifty percent. Do you buy more, sell it, or do nothing? People want a house answer here. A firm with a house answer is not thinking — it is following a rule.
Everything turns on one distinction: did the thesis break, or did the price move? A quarter that misses because a large contract slipped a month, while unit economics keep improving, is a price move. A regulator rewriting the rule the entire model depended on is a broken thesis. On a screen both look identical.
This is why we write down what would have to be true before we buy anything, and why the post-mortem on a loss is a standing obligation rather than a courtesy. A written record is what makes the later question answerable at all. Memory is not neutral; it revises itself in your favor, quietly and at no charge.
Doing nothing is a legitimate answer and an underrated one. When the evidence is genuinely mixed, acting is expensive and uncertainty is itself information. What is not permitted is doing nothing because the decision is unpleasant — the paralysis that looks like patience and costs like a mistake.
The hardest part is social rather than analytical. Someone argued for this position, and that person is usually in the room. Which is why the meeting attacks the thesis and not the analyst, and why changing your mind in front of the group counts in your favor here. A culture that punishes reversals does not get fewer mistakes. It gets slower ones.
A portfolio is not a collection of decisions you once made. It is a set of positions you are choosing to hold right now, and the only question that matters is whether the evidence still supports the choice.