The rule I wrote the night I gave back the month

By Mirco Neri

On a Friday in September I lost $647k in one afternoon.

I was long European diesel into the close. The market went illiquid the way it does when everyone is positioned the same way, and I did the thing every trader knows about and does anyway. I did not want to take the loss. A fifty thousand dollar exit was there. I watched it become a hundred, then more, because getting out felt like admitting I had been wrong, and by the time I admitted it the liquidity to exit at any reasonable level was gone. I cleared everything. A month of gains, including a $400k week that had felt like the start of something, gone in a session.

The market moved, but the loss was mine. Wrong size for the liquidity, wrong attachment to being right. That part hurts more than the number, and it is also the only part worth writing about, because it is the only part that transfers.

I wrote the rules that night, not the next week.

That evening I sat down and wrote what had actually happened and what I would do differently. Rules, in the imperative, written to the version of me who would be at the screen on Monday:

• If long into the closing auction, sell before the close, or immediately after, before it goes offered.
• If there is no clear setup at the close, stay out entirely.
• Trade only when the setup is live and clear.

The reason to write them that night is that a lesson has a half life. By Monday the sting is duller and the memory is already rewriting itself into "the market was unfair." By the next good day the lesson is gone and you are back at the same size in the same illiquid close. Winning often teaches you nothing. Losing teaches you everything, for about seventy-two hours.

I took a day to observe before trading again. On Monday I sat on my hands for the first session and went smaller when I did trade, especially around the close. I finished the day up fifty thousand. Then I nearly did the second dumb thing traders do. I started turning the good day into a principle: patience plus aggressive risk management, look, it works. A tool I use flagged it. It filed the win as a temporary observation and kept Friday's rules as the permanent ones. It was right. Rules come from losses. A win only tells you the rule held for one day.

The mechanism that made the rules survive is a tool I built for myself, and I will say that plainly because I could not find one that did this.

Since the summer I have used an app that asks me one question every evening and gives me a short briefing every morning. The night of the loss, the question was what felt important to remember from the week. The rules above were my answer. On Monday morning, before the Singapore window, the briefing opened with them, in my own words, ranked above everything else I had said that month. It did not cheer me up. It said: here is your plan, you wrote it Thursday, this is a reset, size down, cut early, take profit before the exit gets crowded because everyone is in the same trade.

That is the entire edge. Every trader has rules. Very few traders get their rules handed back to them at the moment they are about to break one, by something that remembers what they decided while thinking clearly and holds them to it when they are not.

I have scored that morning briefing every day for fifty days, zero or one, on whether it told me what mattered or just what I had said most recently. Forty-eight ones. I am a hard grader.

The app is called Athena and it is invite only while it is small. I built it for myself first. A few other people use it now. The practice does not need the tool: write the rule the same night, in the imperative, to Monday you. Then find any way at all to make sure Monday you reads it before the open. I got that wrong for fifteen years, and it cost me more than $647k to learn.

Mirco Neri trades energy derivatives from Dubai. athenaos.net