Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Why would I pick a specific ETF over an equivalent Mutual Fund?
Something to consider is how do you want to handle fractional shares. Most open-end funds can easily go to fractional shares to that if you want to invest $500 in a fund each month, it is a relatively easy transaction where some shares will be fractional and handled easily. An ETF may not always work that way unless you go through something like Sharebuilder that would allow the fractional shares as if the ETF is trading at $150/share, you could buy 3 shares but still have $50 that you want to invest but can't as stocks trade in whole share numbers usually. This is without adding brokerage commissions. Depending on the broker, re-investing dividends may or may not be that simple as fractional shares could be a problem since those 3 shares aren't likely to have enough of a dividend to equal another share being bought with the proceeds. If you want the flexibility of stop and limit orders then the ETF may make more sense while the open-end fund is simply to invest whole dollar amounts that then lead to fractional shares. Don't forget to factor in minimums and other stuff as VFIAX may have a bit of a minimum to it as well as possible fees that could be annoying as I remember VFINX having some account maintenance fees that were a bit irksome back in the day that may still be around in some cases so be sure to read the fine print on things.