DnB of Oslo, the largest financial-services entity in Norway, established in 2014 the promotion of gender equality as a “principal target.”

The bank is partly owned by the Norwegian Ministry of Trade, Industry, and Fisheries, but it wasn’t feeding investors a line about its pledge: At the end of last year, women represented 37% of the top four management levels, according to DnB’s latest annual report, up from 31% in 2014. The goal is 40%.

Similarly,...