A new study has found an interesting consequence of having more women on a company's board of directors: Fewer acquisitions.

The researchers, from Insead, the University of Notre Dame, and Singapore Management University, looked at 1,500 S&P companies between 1998 and 2010. On average, about 10 percent of the board members of these companies were women. (Had the data been collected last year, the number would have been closer to 17 percent.) Then they looked at how many acquisitions each company made during that time, and how large the acquisitions were. It turned out that compared with all-male boards, companies with just two women on their board of directors:

  • Made 18 percent fewer acquisitions
  • Spent 12 percent less on purchasing other companies
  • Spent $97.2 million less on acquisitions each year

This study found differences in company behavior even if only one woman was on the board. "We tried to look for an inflection point, that hockey-stick curve," says Craig Crossland, an associate professor of management at the University of Notre Dame and one of the researchers. "We didn't see that. The effect kicks in pretty quickly and increases the more representation you have."

This paper's findings are in line with those of an earlier study of Norwegian public companies, which by law must fill 40 percent of their board seats with women. After the law was passed and gender diversity on boards became mandatory, layoffs at their companies decreased. "Sometimes firms jump toward layoffs when they're not doing so well," says Crossland. "There is a strong relationship between acquisitions and turnover, so that makes sense to me."

The study cites earlier research showing that generally homogenous groups, such as a board of directors, function differently when other so-called subgroups are included. That could be women or people of color, but age or background could also play a role. "With increased female representation, you tend to get more thoughtful, more detailed, more comprehensive, and perhaps more combative decision-making at the board level," says Crossland. 

And although the companies studied made fewer acquisitions, it's not possible to know, from the research, if overall that was a good thing or a bad thing. The research cites other studies saying acquisitions are often destructive of shareholder value, but that it's hard to measure the long-term impact. In general, Crossland says he believes that the slowed-down acquisition pace of the companies with women on their boards is a good thing. But he says it's "certainly possible" that these companies may have missed good opportunities, too. And, he adds, there are some situations in which speed may be of the essence. "Maybe you should make a slightly worse decision more quickly."