US investment bank Goldman Sachs (GS) wants to know how many of its workers have received a coronavirus vaccine as they return to the office.
According to a memo seen by several organisations, including the BBC, the Wall Street bank told employees that responses were required by 12pm US EST time on Thursday (17:00 BST).
While it "strongly encouraged" its employees to get a COVID jab, the bank said it understood that the "choice to get vaccinated is a personal one."
"Registering your vaccination status allows us to plan for a safer return to the office for all of our people as we continue to abide by local public health measures," the memo, first reported by the New York Times said.
Goldman's US employees are expected to return to the office on 14 June, the bank said last month, and workers who have been vaccinated can work in the office without a mask.
It is unclear whether UK workers were told to provide vaccine proof, however employees were previously told they should expect to be working on-site from 21 June — the date on which the government hopes to lift legal limits on social distancing in England.
The Wall Street bank's latest measures come after staff complained about working "inhumane" hours. A leaked internal report in March this year showed junior workers complaining of working 100-hour work weeks, with one respondent calling it "arguably worse" than foster care.
A Goldman presentation titled "Working Conditions Survey" posted on Twitter (TWTR), detailed dissatisfaction among junior members over long hours and unrealistic demands. The presentation, dated February 2021, showed analysts complaining about worsening mental and physical health, "workplace abuse" from management, and poorer relationships with friends and family.
Returning to the office in a vaccinated world has raised concerns in UK workers who worry that workplaces could make proof of a COVID vaccine a mandatory requirement.
A study by HR software provider and employment law advice service BrightHR, showed half of British workers expect bosses to demand a vaccine passport before they can return to work.
Alan Price, CEO of BrightHR, said: "Although half of people expect their employer to demand a vaccine passport, it remains to be seen how reasonable those demands are and, therefore, whether the employer is acting lawfully in doing so."
Price warned employers to "tread carefully" when requiring workers to have a vaccine and ensure that their "circumstances are appropriate."
"It may well become that the government will require employees in some sectors to have the vaccine, and the passport will be a simple way of evidencing that," he added.
Watch: COVID passports: key to normality or discrimination?