<prompt> Human: I recently funded in full a roth IRA for 2017 5,500 but Im not sure if it is wise to invest it right now while the market is jumping to record highs. While I plan on investing in index funds such as the NASDAQ composite or SP 500 composite and I know that the general rule is that time in the market is better than timing the market but I cant seem to shake the bad feeling about investing those funds at this point in time. Does anyone have some information about how to handle a situation like this?  <response>: The best possible 40 year return on a lump sum investment in the history of the SP was if you invested 8 years prior to the Great Depression Even though you suffer the largest market downturn in history, you would have still slightly beat the returns of perfectly timing that investment at the bottom of the crashEven if you put that lump sum in at the peak right before the Great Depression as long as you held youd still end up with nearly a 10x multiplier over 40 years.Moral is, dont try to time the market. Start now, set things on autopilot, and dont let yourself react to market fluctuations.Source: 