Managers of funds aimed at investors with similar anticipated retirement dates use a wide variety of asset-allocation strategies.

Managers of “target date” funds usually say they will shift toward more conservative asset allocations as participants get closer to their retirement target dates.

A look at the assets of 58 funds designed for workers planning to retire in 2020 shows that the amount of holdings invested in stock, stock funds and related instruments varies from 51% to 95%, according to researchers at Financial Research Corp., Boston.

About 27% of the funds invest in at least one non-traditional asset class, such as commodities, real estate or emerging markets investments.

About 45% of the funds participating in the survey said they use the S&P 500 as their primary benchmark, the FRC researchers report.