For many investors, managing a 401(k) feels like a separate task from managing the rest of their money.
You choose a contribution rate. Pick a target-date fund or a few investment options. Maybe check in once or twice a year. Then the account mostly sits on autopilot.
But for many households, the 401(k) is not a minor account. It may be one of the largest and most important pieces of the overall portfolio. And when it is managed in isolation, the broader plan can become fragmented.
That fragmentation often shows up in subtle ways. An investor might own an S&P 500 fund in a 401(k), another similar fund in an IRA, and more U.S. large-cap exposure in a taxable brokerage account. Or they may hold bonds in a taxable account while keeping a tax-advantaged retirement account invested mostly in equities. None of these decisions is necessarily wrong on its own. But together, they may not reflect a coordinated strategy.
The key point is that investors do not really have “a 401(k), an IRA, and a brokerage account.” From a planning perspective, they have one portfolio spread across multiple account types.
That matters because each account has a different role. Some accounts are better suited for growth. Others may be useful for tax management, income planning, or future withdrawals. The investment decisions in one account should be informed by what is happening in the others.
Historically, this has been difficult because many advisors could not directly manage employer-sponsored retirement plans. As a result, 401(k)s were often left outside the broader investment process.
That is beginning to change. New tools can help advisors incorporate 401(k) assets into a more coordinated portfolio strategy.
The biggest 401(k) mistake, then, is not always choosing the wrong fund. It is treating the account as though it exists by itself.
A better question is: How does your 401(k) fit into the full picture?