

The Market Timing Game simulation is premised on the idea that buying-and-holding index investing and index funds are a no-brainer investment strategy and market timing (i.e. trying to predict market direction and trading accordingly) is a less than optimal strategy. The saying goes “Time in the market not timing the market”. In this simulation, you are given a 3-year market period from sometime in history (between 1950 and 2018) or you can run in Monte Carlo mode (which picks randomly from daily returns in this period) and you start fully invested in the market and can trade out of (and into) the market if you feel like the market will fall (or rise). The goal is to see if you can beat the market index returns.



If you get the 80’s movie reference to “WarGames”, then you might guess the best way to avoid losing the Market Timing Game.



Another way to put this is just to buy and hold. Put your investments into low-cost index funds and don’t worry (too much) about the ups and downs of the market. They always happen, but over time, stocks tend to go up and trying to time when to get into or out of the market leads to sub-optimal result for most regular investors and even many professional investors.

Data and Tools: Daily, historical dividend adjusted prices for the S&P500 stock index (between 1950 and early 2020) were downloaded from Yahoo! Finance. The game was programmed in Javascript using the Plot.ly engine to create the graph.

Update: Added a Monte Carlo mode which lets you play with data that is randomly generated from the daily returns of the S&P500. The probability of a daily return being picked is the same probability/frequency that it occurred in the last 68 years.