If you’re at a mid to large size company your direct managers likely don’t have any authority to give a bonus. There’s simply no budget they have access that go directly into paychecks.
I like the idea of trying to help your coworkers but I worry that rumor would be more disappointing to them vs any positive outcome.
I made the mistake of becoming a manager about 4 years ago. This is one of the most frustrating parts of the job. If you have a good relationship with your team they’ll usually tell you something like “I’ve been getting contacted about other offers, here’s what they’re offering.”
It’s usually about a 20% bump. I’ve not once been able to convince the company I’m at to match it. Usually the best I’m allowed to do is something like a 5-6% raise in the next salary increase cycle.
I’ll usually know for 2-3 months a team member is leaving before it actually happens because of this. Of course, if I’m allowed to hire a replacement they’ll let me pay market value.
Job hopping is definitely the best way to get a pay increase.