Price Still Slight

DO THE CHEAPEST index funds always win? A year ago, I tackled that question—and the results for 2017 were mixed. Since then, the question has become even more intriguing. Last year, Fidelity Investments launched four index-mutual funds with zero annual expenses, while also slashing the expenses on its existing index funds.
Those zero-cost funds have only been around for a handful of months, so it’s a little early to gauge their performance. Ditto for the price cuts for other Fidelity index funds;