CHICAGO—Although the REIT sector excels the broader market in a number of governance areas, the makeup of REIT boards would benefit from greater diversification. That's among the conclusions of a study commissioned by Ferguson Partners Ltd. and issued Wednesday.

The study, which compared 151 non-mortgage REITs with the broader Russell 3000 index, found that demographically, REIT boards are likely to be predominantly male as well as older. Although just 21% of REIT boards are all-male, compared to 25% of all Russell 3000 companies, 73% of REIT boards have no more than one female director. In comparison, 39% of Russell 3000 boards have two or more female directors, compared to 27% for REITs.

Even as most directors of publicly traded companies are in their 50s and 60s, those serving on REIT boards are more likely to skew older. One-quarter of REIT directors are 70 or older, compared to 19% for all Russell 3000 companies. At the other end of the spectrum, REIT directors are slightly less likely to be under age 50.