Mary Williams Walsh / New York Times News Service

It is one of the biggest conundrums of an aging society: Americans have salted away $11 trillion in retirement plans, yet millions still risk running out of money in old age.

On Thursday the government said it had some new tools to deal with the problem. The Treasury issued several new regulations intended to make it easier, and maybe cheaper, for middle-class people in retirement to transfer the money they accumulated in their 401(k)s into an annuity that would guarantee monthly payments until they die.

“Having the ability to choose from expanded options will help retirees and their families achieve both greater value and security,” said Treasury Secretary Timothy Geithner.

The Labor Department also said it had completed rules to let workers learn about the fees various financial firms charge for helping to run 401(k) plans. Labor officials said they thought employers could negotiate better terms if the details were more easily available.