About

Tested Markets is run by Raemin Kang, a software developer in Seoul who builds backtesting tools for personal investing.

Most investing rules are shared without evidence. This site tests them on long-run data from many countries, and reports what held up and what did not.

How a test is made

Each test starts from a script run on the data described in the post. Every number in a post comes from that run. Before a post goes up, the numbers are checked against the original output, and the code is reviewed for common backtest mistakes, such as using prices that were not yet known.

Rules that failed are published too. A rule that lost to simply holding the market is a useful answer.

The data sources, costs and checks are described on the method page.

Nothing here is investment advice.