Investing
Pick a broad, cheap, liquid ETF you will hold. Expense ratio matters. So do tracking difference, bid-ask spread, structure (ETF vs mutual fund), and whether you already own the same market in a 401(k).
Updated 2026-09-08 ยท 8 min read
1) What market? Total US, total world, or a target-date that holds both. 2) Expense ratio under ~0.10% for beta. 3) AUM large enough that the spread is pennies. 4) Tracks a published index. 5) You will still own it during a 30% drawdown.
Sector, leveraged, single-country, and thematic ETFs are products. A portfolio is usually one or two broad funds plus your 401(k).
ETFs rarely dump capital gains the way some mutual funds do. That helps in taxable accounts. If your 401(k) is already an S&P 500 index, buying another S&P 500 ETF in the IRA clones you, it does not diversify you.
Run the numbers: compound interest calculator.
Usually for the same index. Check tracking difference, not just the advertised expense ratio, and confirm the fund is large enough to trade tightly.
Any large, plain S&P 500 or total-market ETF from a major issuer is close enough. Do not pay a commission to switch tickers for 2 basis points.
In a brokerage, ETFs are usually more tax-efficient. In a 401(k), use whatever share class is cheapest in the plan.
Educational only. Verify IRS limits and loan quotes before acting.