Binary events do not belong in a concentrated position

The index traded at 206.55 this morning, -1.99% on the session. I want to write about structure rather than any particular company, because in this sector structure is most of the outcome.

The thing that makes biotech different

In most sectors, work produces edge. You read the filings, understand the industry, and arrive somewhere the average participant has not. Slowly, unevenly, but it accumulates.

A clinical readout does not work like that. The result exists already, sealed, and no amount of analysis moves your probability much. You can assess the science, the trial design and the precedent, and still be facing something close to a coin flip on the day.

What that implies for sizing

If the outcome is genuinely unknowable, then concentration is not conviction. It is a bet with extra steps.

• Basket exposure across many programmes rather than a position in one
• Position sizes assuming a total loss on any individual name, because that is a real outcome here rather than a theoretical one
• No averaging down into a readout, ever, since the thing you are adding to has not become cheaper, only closer to resolution

Why the index rather than the names

Because the sector's returns are driven by a small number of very large winners, and I do not believe I can identify which in advance. Owning the distribution captures that without requiring anyone to be right about which programme succeeds.

In a sector where the outcomes are binary, diversification is not a compromise on conviction. It is the only honest expression of what you actually know.

Where this leaves me

Preferring the index to the names, watching the catalyst calendar with interest rather than intent, and refusing to be talked into a single name view by a compelling scientific story. The compelling story is a poor guide, because the failed programmes had compelling stories too, right up until the readout.