For most investors, low-cost index funds and ETFs are nearly interchangeable. 'Nearly' is where the money hides.
In a taxable account, ETFs usually edge ahead on tax efficiency. In a 401(k), the wrapper barely matters.
Where they differ
The exposure is the same; the plumbing isn't.
- ETFs trade intraday; funds price once a day
- ETFs are typically more tax-efficient in taxable accounts
- Mutual funds allow easy automatic investing
The honest answer
Pick whichever you'll actually contribute to consistently. Behavior beats basis points.
The Bottom Line
Costs matter, but consistency matters more. Automate, stay cheap, and ignore the noise.