In deciding between maxing out 7% interest rate student loan repayment on the other hand, and investing in a SPY ETF on the other there are essentially two factors:
1) Is a projected/historical 8% better or worse than a guaranteed 7%.
2) Does the liquidity advantage of holding the SPY overpower the advantage (if one exists) of the loan repayment.
I figure that the second question has to do with personal preference. However, with a fairly basic assumption I think the first factor is more or less substantial enough to warrant a discussion.
One reason to prefer a guaranteed rate, is if the money is "needed" for something, like retirement income. However, assuming one is under 30 and is not concerned with having a reasonable amount of retirement income, is one answer objectively better than the other?