BlackRock Inc., the world's largest asset manager, has asked its staff to return to office at least four days a week, according to an internal memo seen by Reuters.

"We will shift to at least four days per week in the office, with the flexibility to work from home one day per week," the memo said. "This new approach begins on the 11th of September."

The New York-based asset manager joins other major Wall Street firms in changing its work-from-home policy as financial institutions start to look beyond COVID-19-induced restrictions.

Last month, J.P.Morgan Chase & Co, the United States' largest bank, asked its managing directors to work from office five days a week.

J.P.Morgan CEO Jamie Dimon, along with Wall Street counterparts at Goldman Sachs Group Inc and Morgan Stanley, has been a strong advocate of in-office work.