More than 170 general counsel who collectively spend hundreds of millions of dollars on legal services have told law firms they will take their cash only to law firms that can show they are diverse.

The letter, by the GCs for Law Firm Diversity network, set up last year, is signed by US-based GCs. However, Michelle Fang, chief legal officer at car-sharing platform Turo, who posted the letter, says the group 'would welcome those across the pond and globe'.

The letter says: 'We expect the outside law firms we retain to reflect the diversity of the legal community and the companies and the customers we serve. We applaud those firms that have worked hard to hire, retain and promote to partnership this year outstanding and highly accomplished lawyers who are diverse in race, color, age, gender, gender orientation, sexual orientation, national origin, religion, and without regard to disabilities.'

However, the letter continues: 'At the same time, we are disappointed to see that many law firms continue to promote partner classes that in no way reflect the demographic composition of entering associate classes. Partnership classes remain largely male and largely white. We have no doubt that these lawyers worked hard to earn partnership and deserve the success they have obtained at your firms. We also know that there are women, people of color, and members of the LGBTQIA community and others who are no doubt equally deserving, but are not equally rewarded.'

A commitment to diversity during the recruitment process or hiring a diversity and inclusion officer are not enough, the letter says. 'We, as a group, will direct our substantial outside counsel spend to those law firms that manifest results with respect to diversity and inclusion, in addition to providing the highest degree of quality representation,' it adds.

This is not the first time GCs have taken advantage of their purchasing power to demand diversity. Two years ago US tech giant HP threatened to withold up to 10% of costs invoiced by firms who did not meet minimum diversity requirements.