One downside of having the CFO on the board, as some companies might see it, could be a better paid and more deeply entrenched CFO.

CFOs on their own boards took in 27.3 % more cash ($89,290) and 34.5% more total cash and compensation ($218,715) than their finance colleagues relegated to the outside. The mean tenure of CFOs on the board was 9.65 years, compared to 5.44 years for CFOs not ensconced in the inner sanctum.

"Recent work shows that the CFO's importance is rising and that the impact of CFOs over certain corporate outcomes outweighs the influence of CEOs," the paper concludes. "Our overall results suggest benefits of CFO appointment to the board of directors, which are not seen in the appointment of more executives in general or the appointment of the COO in particular."

One other possible explanation observed by the authors: It may be that the "entrenchment and increased power" of director CFOs allows them "to concentrate on performing their own responsibilities in a more effective manner."