“We find that the range of appropriate equity asset allocations in retirement is strikingly low compared with those of typical lifecycle and retirement funds now in the marketplace,” Van Harlow writes. “In fact, for retirement portfolios whose primary goal is to minimize the risk of depletion and sustain withdrawals, optimal equity allocations range between 5% and 25%.”

Van Harlow admitted that in the 1990s, he had himself been involved in the design of target date funds with high equity allocations. Technology has since evolved to show the risk of such a strategy, he said.

And, he added, that while he has been in the industry for 25 years, it has been only in the last few years that he has come to appreciate the “sequence of returns” risk, which shows that stock market volatility over time can hurt an nvestor just as retirement begins and have permanent negative consequences on the retiree’s assets.

“We were doing the best we could at the time,” he said. “We were guessing.”

Also at the event, Bob Reynolds, president and chief executive of Boston-based Putnam Investments, spoke of retirement savings in relation to the U.S. debt reduction crisis in Washington, D.C., and congressional proposals to cut the deficit by cutting Social Security and 401(k) tax benefits.

Noting that Americans are currently on track to replace just 64% of their income in retirement—a percentage that would drop substantially if Social Security were cut drastically—Reynolds urged financial reform to be viewed as “a math problem” that can be worked out if done thoughtfully.

“To involve this nation’s savings in deficit reduction is a horrible tradeoff,” he said. “Social Security is a vaccine against elderly poverty, which would be a disaster for this country.”