U.S. has more 401(k) millionaires than ever, report shows

The number of "401(k) millionaires" — 401(k) plan participants with balances of at least $1 million — has reached a record high, new data from Fidelity Investments shows.

As of June, there were roughly 497,000 so-called retirement-created millionaires in the U.S., according to the wealth management firm, which analyzed balances across 26,000 of its customers' accounts. Nearly 399,000 Americans also have a least $1 million in an individual retirement account. 

The key to stashing away such sums? Start early and contribute to your retirement plan consistently over many years, Fidelity said.