Slack records everything you do in an immuteable audit log. It's used by lots of finance companies as well as government institutions ( who have just as strict if not stricter rules ). Also they have lots of features to help with e-discovery, so not only is everything recorded, but getting your needed data out is quite easy.

Symphony chat, what goldmans is trying to aim as the bloomberg IB killer. It's quite nice and designed for banks and API/Bot friendly.

url:https://symphony.com/en-US

Probably Teams. https://docs.microsoft.com/en-us/microsoftteams/security-com...

Genuine question - when I use slack - I'm able to see messages going back to when the channel was created for my organization as well as all files shared by date. I'm not sure how slack doesn't do this well?

We used (and I assume they continue to use, hi COFers!) Slack at Capital One. They are super careful about compliance so I'm sure everything was above board with the regulators.

Mattermost does, and just raised about $70m to do it well. ING is on their website. They have e-discovery tools and it's all hosted on your own cloud/servers.

Mattermost, but you'll have to manage it yourself.

Zulip and a very big disk.

Looked at this, appears to make it difficult by default: https://zulip.readthedocs.io/en/latest/production/security-m...

My guess is most of the major chat players handle this pretty easily -- it's a non-starter for many potential users if you don't. Zulip stores all data indefinitely (including message edits, etc) in its default configuration.

i would guess Microsoft Teams can do this.