JP Morgan just relaxed its office dress code in a huge way

In the continuously relaxing American workplace, three industries have largely resisted the tides of casual dress: legal, banking, and government.

One of those pillars is starting to crack - that is, at least, according to an internal JPMorgan memo seen by Business Insider.

The memo, which went out to all employees, detailed a new office dress code for the bank. It stated that business casual dress would be expanded "firmwide," which "reflects how the way [JP Morgan works] is changing."

In general, suit and tie dress is usually still required for banking professionals for a simple reason: many workers interact with clients for much of their day, which demands a certain formality. Over the years, this has morphed into a custom, which has remained distinct from other companies' dress codes both culturally and geographically.

But no longer can JP Morgan ignore the changing tides of office formality.

"More clients are dressing informally, and many parts of our company are already business casual," the memo reads.

Client-facing employees like investment bankers won't necessarily receive much benefit from the new edict, however, as the memo also notes that "if you're seeing a client you should dress for that client."

"While it may not be possible to dress business casual at all times or in all areas, we believe having a firmwide guideline is the right thing to do," the memo reads.

The memo also cautioned employees against interpreting the new dress code as "weekend casual." According to the company dress code obtained by the Wall Street Journal, athletic shoes, flip flops, sweatpants, leggings, yoga pants, hats, hoods, halter tops, or anything else "distracting, tight, revealing or exceptionally loose or low-cut" isn't allowed.

What is allowed: polo shirts, casual pants, capris, and dress sandals. Jeans are also not considered business casual, according to the dress code.

The move comes after CEO Jamie Dimon returned from Silicon Valley, where he met with companies working on financial technology, cybersecurity, and social media. Dimon's observations led him to conclude that JP Morgan's dress code was significantly out of date. Dimon has already apparently been spotted sans tie, the WSJ noted.

JP Morgan's move is certainly in line with relaxing dress codes around the US and the world, which some company leaders see as an attempt to lure a millennial workforce that desires informality. Millennials are unique in that they desire to work for a company that they see as reflecting their values, according to the Washington Post, and a relaxed dress code could be interpreted as proof of that.

Portia Crowe contributed to this report.