Orbit · Knowledge archive
Red Pen Backtests
Popular trading ideas, tested on decades of US market data with realistic trading costs. Each entry has the full method, results tables, charts and the complete Python code, so your AI agent can rerun the test on your own tickers.
Articles
- One change turned an 8.8% factor into 15.1%
Buying the stocks that bring in the most real cash and shorting the least lagged the market. The picks were fine, but the trade was quietly short half the market. Hedged, it made 15.1% a year. - The round-number effect: $86 million on paper, 3 cents in a real trade
A stock that closes just above a round number tends to beat one that closes just below it the next day. I tested every US stock since 2001: the pattern is real, it turns $10,000 into $86 million on paper, and it disappears once you try to… - Buffett made 20% a year for 60 years. Can a robot invest like him?
A 2018 paper took Warren Buffett's record apart. I rebuilt it on my own data: his four habits, a robot that follows them every month since 2005, how close it came to Berkshire, and the code to build your own Buffett portfolio with your age… - The night effect: the full backtest
Hold QQQ only overnight, or buy and hold? Every rule, cost and number behind the video, the complete Python script, and the results for QQQ, SPY and IWM from 2000 to 2026.