No course. No guru. A mirror.

The market didn’t
take your money.
You gave it away.

“You tell everyone it’s going fine.”

Prove us wrong — take the test Free. No registration. 2 minutes.

Does this sound familiar?

“I tell my partner everything is fine. But every week I add margin just to stay in the game.”

— The person this site is built for

“I took my loss. Then immediately made a bigger bet to get it back.”

— Also that person

“I invest my kids’ money too. I haven’t told them.”

— Still that person

What people experience

“You play the simulation thinking it’s a game. Two minutes in, you think: this is about me.”

“I recognized myself in a decision I made three months ago. And for the first time I understood why.”

“It’s not comfortable. But it’s the first time someone told me the truth about how I invest.”


Free simulation

One decision.
Everything you need to see yourself.

Behind one vault is a winning position. Behind the other two: loss. Choose one — then we reveal a losing vault. Then you get one choice: stay or switch?

It seems like a game. It’s not.

Free — no registration

Ready to see who you really are as an investor?

2 minutes. One decision. Your pattern — revealed for free.

Start the simulation → Completely free. No email required.

Also free

One more simulation.
A different kind of mirror.

FREE SIMULATION
The Kelly Criterion

Mathematics knows exactly how much you should bet on any investment. Most investors bet 3x too much — or too little. Five rounds with known odds. You decide the stake. Then we show you what the formula says.

Start simulation → Free. No email. 5 rounds.
f*
= bp – q / b
The formula most
investors ignore

What you get

€97 — once.
No subscription. No AI. A human.

After the five simulations you receive a personal report — written by us, not generated by an algorithm.

01
Your investor profile
We analyse your simulation data to identify what kind of investor you are. Quick wins or long-term patience? Not what you think you are. What the data says.
02
Your biggest blind spots
An overview of the moments when your emotions take over. Not generic — specific to your pattern. Where do you go wrong? When exactly? And what does it cost you?
03
One concrete rule
Not ten tips. Not a course. One behavioural rule — based on your simulation results — that fits who you are as an investor. Something you can apply tomorrow.
Delivered within 48 hours. Written by a human who almost lost everything — and now understands why.

How it works

Four more simulations.
One honest analysis.
Within 48 hours.

01
You pay €97 — once
No subscription. No upsell. No community. Just the simulations and the analysis.
02
You go through five simulations
Each simulation puts you under a different kind of pressure. Loss. Greed. Social noise. A crash. Your decisions reveal your pattern — not your intentions.
03
A human reads your results
Not an algorithm. Not a template. Someone who knows exactly how it feels to be where you are reads your pattern and writes a personal analysis.
04
You receive your mirror
Within 48 hours. Not what you want to hear. What you need to hear. Three specific things that are costing you money — and what to do about them.

Why this exists

“I went short on Nvidia. It kept going up. I considered borrowing money to make the position even bigger. I didn’t — and that probably saved me. I built Lostfolio because I was the person this site is made for. I know exactly what it feels like to be right about everything — except yourself.”

— Lennard Duyvesteijn, founder Lostfolio

Lennard Duyvesteijn has been investing for over ten years. Not as a professional — but as a private investor who had to figure it out himself. He lost money, made mistakes, and came close to betting everything on one position. The turning point wasn’t a new strategy. It was the moment he learned to trust himself — and to dare to lose.

Since then, he has invested consistently and profitably. Not because the market got easier — but because he changed. Lostfolio is what he wished he had when he started.



About Lostfolio

Built by an investor.
Not a guru.

Lostfolio is a behavioural investing platform — not a course, not an investment advisor, not an algorithm. It is a mirror for private investors who want to understand why they keep making the same mistakes.

FOUNDER
Lennard Duyvesteijn
Lennard Duyvesteijn
Private investor for 10+ years. Schipluiden, NL.
LinkedIn ↗
REGISTRATION
KvK 53718224
Registered at the Dutch Chamber of Commerce.
ALSO BY THE SAME FOUNDER
observingthemarket.com ↗
A look behind the scenes of financial markets — algorithms, pension funds, and how institutional players influence each other.
DISCLAIMER
Lostfolio does not provide investment advice. All simulations are based on behavioural psychology research. Past patterns do not guarantee future returns.

Questions? Contact us at simulation@lostfolio.com



Example report

Wondering what you actually get?
Read a real example.

Below is an example of a personal analysis report — based on five simulations, written for a real investor profile. This is what you receive within 48 hours after completing the simulations.

Not a template. Not a checklist. A personal analysis written by a human, based on your specific decisions.

EXAMPLE REPORT — PDF
Personal Analysis Report
David M. — The Committed Holder
Introduction · Investor profile · 5 simulations · 3 blind spots · 1 behavioural rule

Ready to stop
lying to yourself?

Five simulations. One personal analysis. The truth about why you keep making the same mistake — written by someone who made it too.

Start the simulations — discover your pattern €97 — once — no subscription Delivered within 48 hours by a human, not an algorithm.