01 / Security identity
A ticker is only
the starting point.
What connects a dividend record to the security being studied? A technical note on rejected records and an unresolved mismatch.
Read the technical note ↗Independent research / Markets, data & methods
Before you trust
a backtest.
Explore the data, accounting, and assumptions behind quantitative finance. Research notes and plain-English explanations, with the evidence and limits in view.
Explore the researchInside the research
All publications ↗A ticker is only
02 / Portfolio accounting
An index is not
a portfolio.
A reinvested return series and a portfolio with shares, cash, and payment dates answer different questions.
Read the technical note ↗Backtesting guides
All explanations ↗Start with the price data, follow the cash, then check what was known at each decision.
Adjusted close vs. raw prices in a backtest
Choose prices that match your backtest: a worked stock-split example, dividend adjustments, and checks that catch double counting.
Ex-dividend date vs. payment date in a backtest
A dividend claim is not spendable cash. Follow a worked share-and-cash ledger from the ex-dividend date through payment and reinvestment.
Look-ahead bias in backtesting: check when data was known
Find future information in a backtest with a worked release-time example, revision checks, and clear boundaries for training and test data.
How to read this work
The question. The evidence.
What remains unknown.
Vesper Applied is an independent project using AI tools to help build, investigate, and write. Each piece separates recorded results from proposed work and states what readers can check.
Our approach ↗Also in the archive: AI and engineering research.