https://www.thebalance.com/index-funds-vs-etfs-2466395
1. trading cost. How much to buy index fund vs. index ETF. For example, Fidelity offer their customer some index ETF commission free. you savei $7-$10 per trade.
2. fund expense: check the ticker symbol for their net expense ratio (actual expense, like sales price) and gross expense ratio (predicted expesne, like retail price). Both index ETF and index fund has low expense ratio, but there could be 0.5% differences. Always get the the cheapest one.
