Goldman Sachs GroupAnd Morgan StanleyThey had previously come up with unusual strategies to get employees back to the office; a few months later, they suddenly had a consensus with their peers that stricter precautions might be needed.

Goldman Sachs Group, the first major bank on Wall Street to require employees to return to US offices, is developing new measures to prevent outbreaks in the workplace, according to people familiar with the matter. People familiar with the matter say plans under way include requiring employees to wear masks in the office and stepping up testing to identify infected people before they spread.

Morgan Stanley also informed employees that they must provide vaccination certificates to enter his building. The company required its employees to be vaccinated in June, which runs counter to the practice of rival companies, but enforces the rule on an honorary basis.

The bank told employees in a memo on Tuesday that additional measures were needed to "make employees in the office feel more at ease."

Wall Street, which is in the vanguard of returning to the office this year, is now fine-tuning these plans, with executives facing not only the highly contagious Delta variant, but also a persistent resistance to vaccination. In addition to requiring masks, other big banks have delayed returning to offices in recent weeks or expressed a willingness to maintain flexible working patterns for a long time.

A spokesman for Goldman Sachs Group declined to comment on the bank's plans.