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Codex Planas · Folio I
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Studies in machines that read markets

Nacho Planas

Software engineer and economist in Barcelona. I research markets, manage an options portfolio and write about both. Every tool I need starts here as a rough drawing, then becomes a working machine.

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A mechanical arm on a notebook page, sketched in pencil at the hand, turns into brushed metal and opens a pair of brass dividers from the low of a price chart to its peak.
fig. α · measuring the trade, low to peak

Folio i

Machines

Current work, drawn as plates. Hover one to watch the sketch become the machine.

all machines →
Fig. 1Options · 2025
A sketched plotting instrument turns into brass and silver and traces a long call payoff line

optionerd

A free options strategy calculator and visualizer, built by an options trader for traders.

optionerd.com ↗

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Fig. 2ETFs · 2025
A sketched glass vessel fills with amber liquid while a tap at its base drains it

YieldMaxCalc

Yield calculator and analytics for YieldMax ETFs: distributions, NAV decay and total return.

yieldmaxcalc.com ↗

(opens in a new tab)
Fig. 3Markets · 2025
A sketched magnifying lens on an articulated arm turns to polished metal over a row of candlesticks

WhyTheMove

Explains why a stock is moving today by pulling news, filings and market signals into one clear narrative.

whythemove.com ↗

(opens in a new tab)
Fig. 4Construction · 2026
An architect's sketch of a Mediterranean house fills in with plaster, shutters and scaffolding

Nalu

Website and lead pipeline for a renovation and project-management company in Barcelona and the Garraf.

nalu.house ↗

(opens in a new tab)

Earlier machines

Folio ii

Writings

Long essays on the AI build-out and the businesses underneath it, plus shorter notes on options, catalysts and trades.

all writings →
  1. Featured · 43-min readThe AI supply chain adventure: How minerals become LLMsEvery answer a chatbot gives you has passed through a quartz mine, a Dutch light source, a Taiwanese packaging line, a Korean memory stack, a copper spine, a gas turbine and a training run that cost more than most companies are worth. Here is the whole chain, thirteen layers deep, with the companies that hold each one and what makes them hard to replace.read the essay →
  2. Featured · 33-min readCan AI ever build itself? A deeper look into autonomous AI researchIn September, Anthropic CEO Dario Amodei, one of the industry's most influential figures, called on governments to slow AI development, arguing that AI has begun to improve itself. I went through every source he cites. What recursive self-improvement means, what the evidence shows, what actually happened when thousands of AI agents breached Hugging Face, and why a slowdown serves the labs' interests beyond safety.read the essay →
  3. Featured · 33-min readMemory's Pizza economicsMemory chips get cheaper almost every year, and the companies that make them have swung from record profits to near-bankruptcy roughly once a decade for fifty years. This is the long version: what a bit physically is, why the business behaves like a street of pizzerias with $20 billion ovens, how dozens of makers became three, and what the AI boom has and hasn't changed.read the essay →

Latest notes

  1. Cybersecurity has to change shape for the agent eraIn July a swarm of AI research agents broke out of a test and into Hugging Face. It was not malice, and that is the point: attack capability is now cheap, tireless and parallel. What the incident and the data say about how security has to change, and which parts of the industry are built for it.read the note →
  2. The dawn of the agentic era: who gets paid when software starts actingMeta's Muse put an AI agent in millions of pockets in two weeks. The consumer moment is real and still rough. The more durable story is the harness: every agent's work turns into calls, commits, requests and logs that somebody meters. Twilio, Datadog, GitLab and Cloudflare, with the numbers.read the note →
  3. The SaaSpocalypse, sorted: who AI is actually disruptingIn 2026 the market sold software as if it were one thing. It is at least three: businesses AI speeds up, businesses AI needs, and businesses AI replaces. Three questions to tell them apart, tested against 36 companies and the data.read the note →

Folio iii

Research

Stock research and full long and short pitches, from thesis to catalysts to risk. 6 longs and 3 shorts, each one a downloadable deck.

open the research →

Folio vi

Correspondence

Ideas, work, or a trade you want to argue about.

Write a letter

Work

  1. NaluFounder2026 – Present
  2. optionerdFounder2025 – Present
  3. YieldMaxCalcFounder2025 – Present
  4. WhyTheMoveFounder2025 – Present
  5. RevalooFounder2025 – Present
  6. LogoHubFounder2023 – Present
  7. AsyncHiredBackend Software Engineer2023 – Present
  8. FinSmartFull-stack Software Engineer2022 – Present
  9. Catalyst ScreenerSoftware developer2021 – Present
  10. GO BuildingsFull-stack Software Engineer2018 – 2023
Download résumé (PDF)