The composition of pension portfolios is not generally disclosed, so trends are hard to track.

In 1986, only about 30 percent of the pension portfolio was invested in stocks.

The Labor Department issued regulations encouraging companies to actively monitor securities in their pension portfolios.

That particular example from my self-invested personal pension (Sipp) portfolio is Alliance Trust.

Thus, historically, since the average pension portfolio is a mix of stocks and bonds, the average return on investments has been well below 9 percent.

As interest rates fall, corporations must set aside more money for pensions because the securities in their pension portfolios are expected to earn less.

Thompson has worked to diversify the pension portfolio from primarily public equities into private equity, real estate and other asset classes.

And it means that the value of many of the stocks, and especially of the bonds, in a pension portfolio have increased.

He feels that most stocks traded on the exchange are far too speculative to be included in pension portfolios.

Professor Bodie says the agency should begin charging premiums based on the riskiness of a company's pension portfolio.