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

Should I continue to invest in an S&P 500 index fund?
You shouldn't. The Dow has gained 7% annually on average since October 1915(inflation-adjusted). It has also lost 73% of its inflation-adjusted value from 1966 to 1982 meaning that it would have lost you 4.5% annually for 16 years. Furthermore, past performance is not indicative of future results. If stock markets keep performing like they have for the past 100 years, you can expect there will be a point within the next 60-or-so years your stocks will be higher in value than they were when you bought them. With funds you are paying the people managing them which means you are guaranteed to have pyramiding losses that your gains will have to offset. In your case, you are betting with no fundamental knowledge that S&P will be higher than now whenever you need the money which is not even supported by the above assumption. Dollar averaging just means you will be placing many bets which will reduce your expected losses(and your expected gains) when compared to just buying $100K worth of S&P right now. Whatever you invest in, and whatever your time-frame, don't gamble. If you can't say this company(ies) will be $X more valuable than now in X months with probability > Y, then you shouldn't be investing in it. Nobody ever made money by losing money. There are also safer investments than the stock market, like treasury bonds, even if the returns are lousy.