(This is in a B2B context, so "client" here means a company's representative.)
I have a very good working relationship with my client, even if we've been working together only for about a year. My company's relationship with his actually improved pretty quickly when he took charge after the previous manager left.
Something interesting happened recently. During a meeting, he started talking a bit about his company's future plans regarding their collaboration with us. Things are still hypothetical/in discussion and he asked me not to talk about this to my superiors yet. On the other hand, my managers have repeatedly told me how I'm the company's employee first and foremost and thus the company comes before the client. (which probably sounds obvious, but I'm really not "corporate-minded" so they felt the need to stress this)
No matter how I handle this, I think it can be framed negatively:
- If I keep the secret, I'm technically being a bad employee and not doing a certain part of my job. And things could get unpleasant if they somehow learn about it. (though there's literally zero risk of me losing my job because of it)
- If I do go to my hierarchy and tell them about this, then I'm breaking my client's trust. And I can't control how they will use this information - they could let it slip at some point during a meeting or an email, which would obviously do heavy damage to our (well, my) relationship with the client.
Now personally, I value trust and honesty very highly so I'm certainly going to keep my mouth shut until things become official (expected to be in a few months). I also feel like the potential negative of this choice is much smaller than for the other one, though the positive is just "Nothing happens" as opposed to "My company can start preparing plans a bit in advance". But I think it is an interesting question and I'm curious about this community's thoughts on the situation.
Note: the "secret" is basically about how they're looking to potentially either extend or reduce the scope of our contract with them. He wasn't telling me that his company is about to commit a fraud or anything illegal.