Offer your thoughts or opinion on the input financial query or topic using your financial background.

What is the easiest way to back-test index funds and ETFs?
Back-testing itself is flawed. "Past performance is no guarantee of future results" is an important lesson to understand. Market strategies of one kind or another work until they don't.  Edited in -- AssetPlay.net provides a tool that's halfway to what you are looking for. It only goes back to 1972, however. Just to try it, I compared 100% S&P to a 60/40 blend of S&P with 5 yr t-bills (a misnamed asset, 5 yr treasuries are 'notes' not 'bills') I found the mix actually had a better return with lower volatility.  Now, can I count on that to work moving forward? Rates fell during most of this entire period so bonds/notes both looked pretty good. This is my point regarding the backtest concept.  GeniusTrader appears more sophisticated, but command line work on PCs is beyond me. It may be worth a look for you, JP. ETF Replay appears to be another backtest tool. It has its drawbacks, however, (ETFs only)