# 401(k) has a hidden "give money for free" mechanism that most people don't understand.
In many American workers' 401(k) plans, employers will provide **employer match** — you save a portion, and the company adds another portion for you. The average level is 4% of your salary contribution, and the company directly doubles it.
In other words: **instant 100% return rate**.
Comparing the returns of the stock market: The long-term average annual return of the S&P 500 index is about 10%, which takes 7 years to double. But how does this 401(k) match up? Every month on payday, you get a 100