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Clarsachaxa UK markets journal

Newton Abbot · London hours

Machine learning, written for people who sit in front of a market.

Clarsachaxa is a UK journal on where models earn a place on a desk, and where they only decorate a slide. We follow forecasting, risk, portfolio construction and execution through gilts, sterling, listed equities and the London close.

Read the desk notes UK market map

Commentary and education. Not a personal recommendation, not a signal service, and not an invitation to deal.

A London dealing floor seen from behind a row of desks, monitors glowing with abstract charts

From the journal

Notes worth the commute

All desk notes
A fountain pen beside a blurred printed chart on an oak desk

12 October 2026 · Forecasting

The earnings model that cheated

A language model looked brilliant on reported earnings until the filing dates were put back in the right order.

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Four people in a bright meeting room discussing a market problem, faces turned away

28 September 2026 · Risk

Gilt stress is a collateral problem

A value-at-risk number that ignores margin, convexity and who has to sell is a caption, not a control.

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A researcher seen from behind, studying a wall of softly blurred charts in a bright studio

9 September 2026 · Portfolio

Stamp duty inside the optimiser

A half-percent charge on most UK share purchases will humble a model that was trained as if turnover were free.

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An angled monitor showing an abstract green and sand heatmap with no readable figures

19 August 2026 · Execution

The close is a market of its own

On the London auction, the useful question is not the mid-day imbalance. It is what still matters in the last minutes.

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Four desks, one standard

Use cases we keep returning to

Machine learning in markets is not one product. It is a set of jobs with different clocks, different data mistakes, and different ways to lose money politely.

A quiet data hall with amber status lights along dark cabinets Forecasting Nowcasts of UK activity, short-horizon volatility, and the unglamorous work of stopping a model from reading tomorrow’s filing today. A green banker's lamp beside stacked cream folders on a dark desk Risk Tails, liquidity, factor crowding and scenario libraries for a gilt move, a sterling gap, or a power-price week that does not resemble the training set. A walnut research desk with two monitors of blurred charts, tea and a linen notebook Portfolio Optimisers that respect constraints, costs and estimation error, instead of treating a covariance matrix as a personality. Wet City of London pavement reflecting warm office windows at night Execution Implementation shortfall, child orders, venue choice and the closing auction. The part of the P&L that research slides tend to round away.

How a note gets published

Four tests before we trust a picture

  1. 01 Point-in-timeIf the feature could not have been known at the decision, it does not belong in the backtest. Revisions, restatements and index membership all count.
  2. 02 A gap between train and testOverlapping labels leak. We would rather look poorer on a chart than smuggle next week into this week’s fold.
  3. 03 Costs a UK desk actually paysSpread, impact, stamp duty where it applies, and the boredom of not being filled. A hit rate is not a strategy.
  4. 04 Prose a risk manager can readIf the use case cannot be explained without a leaderboard screenshot, it is not ready for this journal.
Morning light on a British research desk with tea, a notebook and blurred market screens
The desk standard: a claim has to survive the notebook, not only the notebook computer.
Early morning in a Devon market town, wet stone and a small river bridge

Why Newton Abbot

Close enough to the tape. Far enough from the noise.

The clarsach is a small harp that still fills a room. We borrowed the name because that is the scale we want: precise, local, audible over a noisy global tape. The journal is edited at 32 Bugle Place. The markets it writes about open in London.

About the desk

Bring a use case, not a pitch deck

If you run research, risk or execution in the UK and want a use case pressure-tested in public language, write to the desk. We do not sell signals and we do not manage money.

Contact Clarsachaxa