<prompt> Human: The internet is full of articles about the concept of compounding interest. Thats great. How do I invest in things whose interest compounds?Background: In additional to a 401k, I have a Roth IRA and a regular one from a 401k rollover. These are mostly filled with various Vanguard index funds.However, do I need to make investments that yield interest income and reinvest that interest income in order to benefit from compounding interest? Why is the internet incapable of teaching this seemingly important point? Im missing something obvious, right?  <response>: Any investment where gains are re-invested could be considered to be compounded.Growth companies stocks re-invest in their own business, to achieve the effect of compounded growth. Otherwise, any gain you routinely reinvest, compounds. 