Global businesses have failed to provide detailed and transparent workforce data in response to a request from more than 120 investors managing over $13trn (£11trn) in assets.
Legal and General, AXA IM and Amundi were among the investors to call for more transparent data last year in order to help identify hidden human rights risks.
And although 90 global companies responded to the annual Workforce Disclosure Initiative (WDI), less than a quarter said they monitor wages for their supply chain workers.
Half provided no detail on who is involved in the workforce risk management process, how frequently it is carried out, or what areas of the business are covered.
AXA IM head of responsible investment, Matt Christensen, said: "The data are used to provide in-depth information to our social performance and impact assessment.
"It constitutes our engagement with companies around social considerations and helps us make processes evolve in the right direction at operational and supply-chain levels."
The WDI quizzes companies on topics such as diversity, wages and health and safety in order to improve the quality of jobs in listed companies' operations and supply chains.
Despite many being unable to provide detailed data, the number of disclosing companies more than doubled from last year, and included 21 of the world's largest firms.
Adidas, Microsoft and Toyota were among the 90 companies to respond, which together employ over 8.3 million people and have relationships with more than 1.5 million suppliers.
However, well-known names like Apple and BP declined to participate, citing confidence in their existing public reporting.
ShareAction, which coordinates the WDI, said the lack of detail on how companies manage and protect low paid and supply chain workers warrants further investigation.
"Not least because the reporting process provides insights that benefit corporate governance, and because calls for better data and action to deliver decent jobs are only getting louder," head of programmes, Amy Metcalfe, said.
"But the leadership shown by 90 companies across 11 sectors demonstrates that these challenges can and should be overcome."