## Reference
[wsj](http://guides.wsj.com/personal-finance/retirement/what-is-a-401k/)
## Main
A 401(k) is a `retirement savings plan` sponsored by an employer.
It lets workers save and invest(投资) a piece of their paycheck `before taxes are taken out`.
Taxes aren’t paid until the money is withdrawn from the account.
With a 401(k), `you control` how your money is invested.
Most plans offer a spread of mutual funds composed of stocks, bonds, and money market investments.
The most popular option tends to be `target-date funds`,
a combination of stocks and bonds that gradually become more conservative as you reach retirement.
the resrictions and caveats and others refers from the `#Reference Tag`
## What I learned
supplement 补充
Pension 养老保险
conservative 保守
caveats 警告