The 401(k) is the most powerful wealth-building tool available to most American employees — and it's dramatically underutilized. The combination of employer match, tax advantages, and compound interest makes it the highest-return "investment" you can make before considering anything else.
The basics: what a 401(k) actually is
A 401(k) is a tax-advantaged retirement savings account offered by your employer. You contribute pre-tax dollars (traditional 401k) or after-tax dollars (Roth 401k), the money grows tax-deferred or tax-free, and you pay taxes only upon withdrawal (traditional) or never again (Roth).
Traditional 401(k) vs Roth 401(k)
| Feature | Traditional 401(k) | Roth 401(k) |
|---|---|---|
| Contributions | Pre-tax (reduces taxable income now) | After-tax (no immediate benefit) |
| Growth | Tax-deferred | Tax-free |
| Withdrawals | Taxed as ordinary income | Tax-free (qualified) |
| Best for | High earner now, lower bracket in retirement | Lower earner now, higher bracket expected |
| RMDs at 73 | Yes — forced withdrawals | No (Roth 401k has RMDs, Roth IRA doesn't) |
The employer match: the most important number
If your employer matches 100% of contributions up to 4% of salary, and you contribute 4%, you've instantly doubled that portion of your money. A $5,000 match means you need $5,000 of salary — at a 25% tax bracket — to generate $5,000 take-home. The match does it at no additional tax cost.
What to do with the investment options
Most 401(k) plans offer actively managed funds with high expense ratios (1-2%) and a few index fund options (0.03-0.2%). Almost always, the right choice is the total market index fund or S&P 500 index fund with the lowest expense ratio in your plan's menu. If there's a target-date fund with low fees, that's another simple option.
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