Questions involving finance and financial markets can be tough. Often one's intuition is misleading, and all kinds of priors and biases can get tangled up in decision-making.
With defined contribution pension plans, college tuition plans, annuities, health savings accounts, etc. it is all the more important for everyone to be able to make good financial decisions.
Here is a very practical issue, with a question that I am pondering. I have intuition on it, but some lingering concerns as well. I will put it out there for others to think about.
So suppose you all of a sudden come upon $1 million. You would like to invest this in the stock market, using just one low cost index fund. Your time horizon is long, say 15 years at least.
Should you put all the $1 million in at once, or should you do something like spread it out over 12 months, putting an equal amount in each month?