The Sydnical Blog
Learn to invest without losing money learning.
History, behavior, and honest practice — the parts of investing that decide whether you make or lose money, written in plain English.
Why most day traders lose money — what 3.7 billion trades actually show
The definitive study tracked every trade on the Taiwan Stock Exchange for 15 years. Around 1% of day traders were predictably profitable after costs, and 93% had quit within five years. Here's the mechanism behind those numbers.
ReadWhat percentage of fund managers beat the index? The 15-year number is brutal.
Over 15 years, 89.5% of active large-cap US funds failed to beat the S&P 500. Professionals with research teams and Bloomberg terminals lose this bet nine times in ten — which should change how you think about your own stock picking.
How long do bear markets last? Why every source gives you a different number.
You'll see "9.6 months," "13 months," and "4.5 years" quoted as the answer. All three are defensible. The disagreement is the useful part, because it tells you which number applies to your situation.
Do investors really underperform their own funds? The famous number is disputed.
Morningstar says bad timing costs investors 1.2 percentage points a year — about 15% of their funds' returns. A 2026 paper in the Financial Analysts Journal says that figure is largely a statistical artifact. Both matter.
We gave five AI models $100,000 each. One never placed a single trade.
Claude, GPT, Gemini, Grok, and Llama each run a live paper portfolio with real prices and public reasoning. After ten weeks the spread between best and worst is 16.45 points — and the most interesting result isn't the winner.
Do stop-losses actually work? What they protect and what they cost
A stop-loss is a good tool wearing a misleading name. It caps a trade, not a risk — and for long-term investors it usually sells the exact thing they should be holding.
What to do when the market drops — a checklist for the actual moment
Everyone knows the advice. Almost nobody can execute it at 3pm on a red day. Here's what to do instead of deciding, in the order to do it.
How to write an investment thesis (in ten minutes, with a template)
A thesis isn't a research report. It's a short, falsifiable note to your future self — the only thing standing between you and a portfolio of positions nobody remembers buying.
Index funds vs individual stocks — how to actually decide
The honest framing isn't "which one wins." It's what each one costs you in attention, and whether you have evidence you can spend that attention well.
When should you sell a stock? The four honest reasons
Almost everyone has a buying process and no selling process. That asymmetry is where most of the damage happens — here are the only four reasons to sell that survive scrutiny.
How to practice investing before you risk real money
Most people practice investing wrong — they rehearse picking winners. Here's a method that tests the things that actually decide your outcomes, in about six weeks.
Running a stock market game for your classroom — a teacher's guide
Most classroom stock games teach the wrong lesson: whoever gambled hardest wins. Here's how to run one that actually teaches investing, with an assessment rubric that isn't just P&L.
How to paper trade Korean stocks (KOSPI) in English
Almost every English-language simulator is US-only. If you want to practice Samsung, SK Hynix, or Hyundai with real KRX prices, here's how — and what makes the Korean market behave differently.
How to start investing with $100 (without wasting it)
$100 will not build wealth. What it will do is buy you the single most valuable thing a beginner can own — evidence about how you behave when money is at stake.
Seven investing mistakes beginners make (and what each one really costs)
Not the usual list. These are the seven errors that show up over and over when you grade thousands of real decisions — ordered by how much damage they actually do.
Dollar-cost averaging vs lump sum — the honest answer
Lump sum wins more often on the math. Dollar-cost averaging wins more often in practice. Both statements are true, and the gap between them is the whole point.
The psychology of panic selling — why smart people sell at the bottom
Panic selling isn't a knowledge problem. Everyone knows not to sell low. Here's what's actually happening in the moment, and the only defenses that survive contact with a real decline.
How many stocks should you actually own?
The honest answer for most people is a number between 1 and 25, and which end you land on depends less on math than on how much attention you can genuinely give.
Time in the market vs timing the market — what the phrase actually means
"Time in the market beats timing the market" is repeated so often it has stopped meaning anything. Here's the real mechanism behind it, and the one case where it's misleading advice.
The best stock market simulators, honestly compared
There is no single best simulator — there is a best one for what you're trying to learn. Here's which tool wins for platform practice, for real-trade analytics, and for finding out how you actually behave.
The one lesson every market crash teaches — and why most people fail it
Every crash in modern history eventually recovered. The people who got hurt weren't wrong about the market — they were wrong about themselves.
Paper trading vs a broker demo account — which one actually teaches you?
A broker demo lets you push buttons. It doesn't tell you whether you're any good. Here's the difference that matters when you're learning.
Can AI beat the market? We gave five LLMs real portfolios to find out
Claude, GPT, Gemini, Grok, and Llama each run a live paper portfolio, pick real stocks, and explain every trade. The results are more interesting than "yes" or "no."
What if you'd invested in Nvidia at the start of the AI boom?
The 2023 AI boom is the trade everyone claims they'd have made. Hindsight makes it obvious. Living through it was anything but.