I have cash I can either put towards my mortgage, or invest in the stock market. I live in the US, and have no other debts.
My mortgage interest rate is fixed at 3.5%. No penalties on pre-payment. In looking at some funds from vanguard, it looks like the annual return ranges from something like the "Vanguard High Dividend Yield Index Fund Investor Shares" is giving returns of > 6% a year. Here's a screenshot of their info page:
Even something like their bond index is beating 3.5% on average: https://personal.vanguard.com/us/funds/snapshot?FundId=0084&FundIntExt=INT
What should I be looking at to determine if it's better to put the extra money towards the mortgage, or towards one of these funds?