The average 401(k) balance, for savers 10 years in, rose to a record of $306,500 in the three months through September, according to Fidelity.
"With the good economy, more people are contributing, they might even see an opportunity to contribute a little bit more," Meghan Murphy, vice president of Fidelity Investments, told FOX Business.
America's unemployment rate is sitting at a near-record low of 3.6 percent.
These "consistent savers" appear to be unfazed by the ongoing U.S.-China trade war and impeachment talks.
With the Dow Jones Industrial Average, the S&P 500 and Nasdaq all hitting fresh records this week, investors holding stocks will probably see their balances grow further.
As stocks keep climbing, President Trump frequently encourages Americans to check their 401(k) plan.
Fidelity, a fund giant with nearly $8 trillion in assets, is also noticing other positive trends, including individual contributions climbing nearly 17 percent since 2014 to an average of $7,120. Workers are saving about 8.8 percent of their salaries, with employers kicking in 4.6 percent, noted Murphy.
Automatic enrollment and, in general, better financial education are also encouraging more Americans to get in the game.
The average balance overall, for new and more seasoned savers, remained steady at $105,200, down less than 1 percent from $106,000 in the second quarter of the year.