By Nupur Anand, Isla Binnie

(Reuters) -U.S. bank JPMorgan Chase on Friday asked its employees who are on hybrid work schedules to return to the office five days a week starting in March, an internal memo seen by Reuters showed, prompting hundreds of staff comments, including complaints.

Financial companies have been aggressive in enforcing return-to-office demands in the wake of the pandemic which began to impact the U.S. in 2020. Many companies began to call staff back to the office as early as 2021.

JPMorgan CEO Jamie Dimon and counterparts at Goldman Sachs and Morgan Stanley have been strong advocates of working from the office, saying it fosters better learning, innovation and culture.

More than half of JPMorgan's employees already come into the office full-time, according to the memo from the bank's operating committee. It has more than 316,000 staff worldwide.

"Now is the right time to solidify our full-time in-office approach," the executives wrote. "We think it is the best way to run the company."  

A JPMorgan spokesperson confirmed the contents of the memo but declined to comment further.

"We know that some of you prefer a hybrid schedule and respectfully understand that not everyone will agree with this decision," Dimon and other leaders wrote in the memo. "Being together greatly enhances mentoring, learning, brainstorming and getting things done." 

Some JPMorgan staffers pushed back against the return-to-office directive by posting comments on the company's intranet site, according to two sources who saw the posts and declined to be identified discussing personnel matters.

The complaints cited increased commuting and childcare costs, as well as concerns about mental health and stress, according to one of the sources.

After more than 300 comments were posted within the first hour, the page was locked, the second source said.

Essential workers at lenders, including bank branch employees, reported for in-person work throughout the pandemic. JPMorgan called corporate staff back to offices on a rotational basis in mid-2021 after months of pandemic shutdowns, and brought managing directors back to the office full-time in 2023.

The largest U.S. lender said that employees will be given at least 30 days' notice before they are expected to return to offices full-time. The employees were also directed to seek manager approval if they needed more time to prepare.

"What is not changing is our support for flexibility in the workplace, which we are committed to providing at every level in a fair way," the bank said.

The memo also included a link to a list of frequently asked questions, giving details about special exceptions for remote work, flexibility for personal reasons and attendance logs.

(Reporting by Nupur Anand and Isla Binnie in New York, additional reporting by Arasu Kannagi Basil in Bengaluru, Editing by Lananh Nguyen, Jane Merriman and Matthew Lewis)