Many corporate financial executives are worried about the risk lurking in frozen defined benefit pension plans as well as in plans that are still open to new entrants.

Researchers in the Stamford, Conn., office of Towers Perrin Inc. have published that conclusion in a report on an informal survey of more than 100 executives at companies with large pension plans.

Although 32% of the participants’ companies have frozen out new plan participants, many of the participants continue to worry about the plans’ obligations, the researchers write.

Pension plan sponsors can insure against most pension plan risk by buying annuities from insurance companies.

But only 28% of the U.S. participants who are worried about pension risk say buying an annuity is a very attractive solution, the researchers write.

Many participants believe using annuities to solve pension risk problems is too expensive, the researchers write.

About 60% of the participants said “financial instruments for managing risk” would be the most attractive solution, and 36% prefer “full-service outsourcing,” the researchers write.