The problem for high yield companies is they are notoriously poor at revealing their social metrics.

“The impact studies done on gender and ethnic diversity at companies that I have reviewed have shown a correlation in performance,” says Kimberley Lewis, London-based engager at Federated Hermes.

Moreover, Hermes’ own credit research has found that the bonds of companies with high ESG scores tend to outperform.

“What’s deeply frustrating,” says her colleague Aaron Hay, lead engager for fixed income, “is that it is generally much harder to identify disclosed workforce data for high yield companies than in investment grade. That makes it difficult to have a meaningful conversation about ethnic diversity or the gender pay gap if you don’t have a starting point. Once you see what performance looks like you can tell what needs to be done.”

That could prove a barrier to sourcing new investments in the coming months. One US company, jeans-maker Levi Strauss & Co, appears to have realised this problem and last month provided an example for high yield borrowers.

“It has publicly disclosed less racial diversity in senior management, despite having an extremely diverse workforce,” says Hay. But this is not the trend, he adds.

Some progress has been made in recent years. In the UK, many companies report a gender pay gap, notes Lewis. Generally, this is because women are over-represented in the lower quartile and under-represented in the top quartile. “I suspect the same is true for ethnicity,” she adds.

“I cannot think of a compelling reason why a company should not disclose the ethnic diversity of their boards,” says Lewis. “There has been movement on gender, with many ESG investors having a target of 30% female representation in the UK and 20% in the US. ESG investors in the UK have been willing to vote against companies that don’t have at least one woman on the executive team. But we haven’t got there yet with ethnicity.”

But industry proposals are in place and recent events have added impetus to these. In the UK, a review of the ethnic diversity of boards by Sir John Parker has suggested companies have at least one person on the board who is from an ethnic minority.