Cycle analysis by Lars von Thienen
Every market has a zeitgeist. Cycles tell you which one you are in.
A zeitgeist is the mood of a time. In markets it has a length, a phase and a direction, and it can be measured. Cycles IQ, the membership by invitation, gives you the instruments that measure it and direct access to Lars.
The research newsletter is open to everyone: research.marketzeitgeist.com
Author of Decoding the Hidden Market Rhythm, Parts 1 and 2 · Finalist, Technical Analyst Awards 2022, two categories · Board member, Foundation for the Study of Cycles
Cycles IQ · Membership by invitation
The full cycles stack, with the person who built it.
Analyzer, scanners, readings
The advanced cycle analyzer and the scanner pages, with extended tools and screens, pre-built dashboards as starting points, and the weekly cycle readings of the research newsletter. The Cycles Knowledge Graph joins stage by stage as it is built.
API, MCP and the AI skills
Full Cycles API and MCP access, from your code or from Claude, ChatGPT and Cursor. The Cycles AI skills let your AI coding tool build screens on the engine. Where agreed in your offer, the stack runs on your own infrastructure.
Onboarding and sessions
A 2-hour onboarding session with a written recap, then 30-minute sessions booked about a week ahead. Updates, maintenance and support are included.
Terms. Membership is a one-time joining fee plus an annual service and update fee, set out in your individual offer. The method and the skills are proprietary, so membership starts with a signed NDA. How it starts. One request, a short questionnaire, a 30-minute call with Lars, then your offer.
Or write to lars@marketzeitgeist.com.
Method and background
Measured, not assumed.
Every reading starts from the data: detect the dominant cycles in a series, score their stability, locate the current phase, and only then project. The same routines run in the research, in the analyzer and behind every API call. Cycle lengths are not fixed in advance; they are found in the data and re-measured as it changes.
- Decoding the Hidden Market Rhythm, Part 1: Dynamic Cycles (2nd edition, 2017). The method for finding and trading dominant cycles, with indicator source code.
- Decoding the Hidden Market Rhythm, Part 2: Metonic Cycles (2014). A non-linear approach to cycles that influence financial markets.
- Finalist at the Technical Analyst Awards 2022 in two categories, Best Specialist Product/Research and Most Innovative New Product, for the cycle analysis technology behind the FSC cycles app.
- Lars von Thienen serves on the board of the Foundation for the Study of Cycles.
Every market moves in cycles, and the cycles morph: a length that dominated a series for two years fades, another takes over, and the right side of the chart no longer matches the one you calibrated on. For twenty-five years I have built the detrending, spectral and validation routines that measure this in the here and now instead of assuming it. What changed is the application layer: with the method encoded as skills, you describe the screen and the AI builds it. The measurement took decades. Using it takes an afternoon. Lars von Thienen, founder of Market Zeitgeist and developer of the WhenToTrade cycle engine, author of Decoding the Hidden Market Rhythm, board member of the Foundation for the Study of CyclesBuilt on the stack
- macro.cycle.tools: a macro regime composite from thirty-one public economic series, open source under the MIT licence.
- scanner.cycle.tools: the reference cycle chart of the cycle charting skill.
- Two builds, live at the Cycles Conference 2026 in New York: the prompts and what came out.
Inside Cycles IQ · Cycles Frontier Technology In build
The Cycles Knowledge Graph: know which cycles to trust.
The scanner tells you which cycles are in a market right now. The graph is built to answer the three questions that follow, which today are answered by experience and by eye:
- Can I trust this cycle? Its age, its length drift, and how likely it is to survive one more swing.
- Is it part of something bigger? How many related markets share the band and turn in the same weeks.
- Has this kind of call worked before? Every projected turn recorded before the fact and scored against what came, including the misses.
Status: in build. The first three what-if questions are running; Findings Report 01 will be the first published result. Members receive each stage as it lands.
Without membership
Other ways in.
Access today. The research newsletter is open to everyone, and FSC members activate the Cycles API as Guest at no cost. The API usage plan opens after the invitation phase. Cycles IQ is by invitation.
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Research Free essays
Read on Substack
The research newsletter
Essays on the method are free. The weekly cycle readings of the markets are for paid subscribers and included in Cycles IQ. The research follows cycles beyond the markets as well: in macro series, in society and in natural data.
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FSC members Free
Activate in the FSC app
Guest access to the Cycles API
For members of the Foundation for the Study of Cycles: analysis of your own data, three stored datasets, 2,000 key calls a month.
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API Usage-based
API plans and limits
The Cycles API and MCP server
Cycle detection, cyclic RSI, phase and projections, priced per token, from your code or your AI client. Opens after the invitation phase. Cycles IQ adds the AI skills, the advanced analyzer, the Knowledge Graph and sessions with Lars.
Cycles IQ starts with one request.
Tell Lars who you are and what you want to measure or build. He replies in person with your invitation: a five-minute questionnaire, then a 30-minute call. The research newsletter is open to everyone.
Write to Lars: lars@marketzeitgeist.com