Americans held $16.6 trillion in retirement assets as of Sept. 30, up 6.1% from three months earlier, according to the Investment Company Institute.
Those retirement assets accounted for 36% of all household financial assets in the U.S., ICI said in a news release.
A strong showing by domestic stocks, marked by the S&P 500 stock index's 11.3% gain for the quarter, helped fuel the gain in retirement assets.
Individual retirement accounts claimed the biggest piece of that pie, with $4.45 trillion, up 7.2% from the prior quarter. In second were defined contribution plans, with $4.25 trillion, up 6.8%; followed by state and local government pension plans, $2.82 trillion, up 6.7%; private defined benefit plans, $2.18 trillion, up 4.9%; annuities, at $1.53 trillion, up 5%; and federal pension plans, at $1.34 trillion, up 1.9%.
Target-date mutual funds continued to attract more assets, climbing to $306 billion as of Sept. 30, up 14% from the prior quarter. Lifestyle funds advanced 8.3% to $248 billion.