How to Choose Investments Inside Your 401(k)

Signing up for a 401(k) is only the first step — you also have to decide what to actually invest your contributions in, usually from a limited menu of options chosen by your employer’s plan. For many people, this is the most confusing part of the whole process.

Understanding your plan’s investment menu

Most 401(k) plans offer a curated list of investment options, typically including:

• Target-date funds: A single fund that automatically adjusts its mix of stocks and bonds over time, becoming more conservative as you approach a specified target retirement year.
• Index funds: Funds tracking a broad market index (like the S&P 500 or the total U.S. stock market), similar to what’s covered in our index funds guide.
• Actively managed funds: Funds where a manager makes ongoing decisions attempting to outperform a benchmark, typically carrying higher expense ratios than index funds.
• Bond funds: Funds focused on fixed-income investments, generally lower-risk and lower-return than stock funds.
• A company stock option: Some plans allow investing directly in your employer’s own stock — worth approaching cautiously, since it concentrates both your income and a portion of your investments in the same company.

Target-date funds: a common default option

A target-date fund is designed as an all-in-one option: you pick the fund matching your approximate expected retirement year (for example, a “2055 fund” for someone expecting to retire around then), and the fund automatically becomes more conservative — shifting from more stocks toward more bonds — as that year approaches.

Advantages: Requires no ongoing rebalancing or allocation decisions from you; a reasonable “set it and forget it” option, especially for those who don’t want to actively manage their own allocation.

Limitations: The specific glide path (how quickly it becomes more conservative) varies between fund providers, and a generic fund built for a target year doesn’t account for your individual risk tolerance or unique circumstances, as covered in our risk tolerance guide. It’s a reasonable default, not necessarily the optimal choice for every individual.

Building your own allocation from index funds

If your plan offers low-cost index fund options, some people prefer building a simple allocation themselves — for example, splitting contributions between a broad U.S. stock index fund, an international stock index fund, and a bond fund, in proportions matching their own risk tolerance and timeline — rather than using a single target-date fund.

This approach offers more control and can sometimes access lower expense ratios than a target-date fund within the same plan, but requires periodically rebalancing the allocation yourself as your timeline changes and as different funds grow at different rates.

What to check about each fund option

• Expense ratio: As covered in our expense ratios guide, lower-cost options generally have an advantage over time, all else being equal.
• What the fund actually holds: Don’t rely solely on a fund’s name — check its underlying holdings and stated objective to understand what you’re actually invested in.
• Historical performance, with caution: Past performance can offer some context, but it’s not a reliable predictor of future results, particularly for actively managed funds trying to outperform a benchmark.

A word on employer stock

If your plan allows investing in your employer’s own stock, it’s worth being cautious about over-concentrating there. Your income already depends on your employer’s success — adding a large investment position in the same company means that if the company struggles, you could face both job security concerns and investment losses simultaneously. Many financial professionals suggest limiting employer stock to a modest portion of your overall portfolio, if you choose to hold it at all.

If you’re genuinely unsure where to start

A reasonable, common default for someone who doesn’t want to actively research and manage individual fund choices: select an appropriately dated target-date fund matching your expected retirement year, direct your full contribution there, and revisit the decision periodically (for example, once a year) rather than trying to build a fully custom allocation from day one.

Where this leaves you

• 401(k) plans typically offer a limited menu of funds, commonly including target-date funds, index funds, and actively managed funds.
• Target-date funds offer a simple, automatically adjusting all-in-one option, though they don’t account for individual risk tolerance.
• Building a custom allocation from index fund options offers more control but requires periodic rebalancing.
• Approach employer stock options cautiously, given the added concentration risk of combining your income and investments in a single company.

Nothing here is personalized investment advice — just general education. Read our full disclaimer for the details.