Americans have accumulated a record $16.4 trillion in retirement accounts, with about half of it in company-sponsored plans like 401(k)s and in Individual Retirement Accounts, according to a study by the Investment Company Institute.

The ICI, a Washington-based trade association, said that the total as of year-end 2006 was up 11 percent from the $14.7 trillion in retirement assets at the end of 2005 and nearly 55 percent higher than the market-depressed low of $10.6 trillion at the end of 2002.

Retirement assets had declined in 2001 and 2002 as the stock market dropped following the bursting of the technology stock bubble and the Sept. 11, 2001, terrorist attacks, but have recovered since, the study showed.

The 2006 savings total included $4.2 trillion in IRAs, $4.1 trillion in defined contribution accounts like 401(k)s, $2.3 trillion in company-sponsored pension plans, $4.2 trillion in government pension plans and $1.6 trillion in retirement annuities, the ICI said.

Sarah Holden, senior director of retirement and investor research at ICI, said the findings indicate Americans "are actively saving for their retirements."ICI senior economist Peter Brady, co-author of the study with Holden, added that the results also "highlight the important role of employer-sponsored plans." Growth of these plans also was contributing to the growth in IRAs because many of the IRAs were funded with rollovers from employer-sponsored plans, he added.

In fact, more than $200 billion was rolled over into IRAs each year from 2002 to 2004, according to the latest available data, the ICI said. The study looked at tax-deferred retirement accounts but did not include assets in taxable savings accounts, investment accounts or other accounts that Americans also might tap for retirement.

The ICI study gave some insight, too, into how Americans save. Traditional IRAs, which are funded with pretax money or rollovers from company plans, had $3.8 trillion in assets at the end of 2006 compared with $178 billion in Roth IRAs, which are funded with after-tax money, the study found.

More than half of the money in defined contribution plans was invested in mutual funds, the study said. The rest was in holdings that included individual stocks, bonds, separately managed accounts and guaranteed investment contracts, Holden said.

Nearly 70 percent of the mutual fund assets in defined contribution plans and IRAs were in stock funds, 14 percent in hybrid stock-bond funds, 8.7 percent in bond funds and 7.4 percent in money market funds.

The study also found that lifecycle and lifestyle funds are increasingly popular with investors. Lifecycle funds, which include target date funds, combine stocks and bonds in an increasingly conservative mix as the investor's retirement approaches; lifestyle funds balance holdings based on the investor's risk profile.
Savings in theses funds grew to $303 billion at the end of 2006, up from just over $200 billion a year earlier. "It really reflects demand by individuals to have their asset allocation and rebalancing made simple for them," Holden said.