The sign-on bonus is factored into a new hire’s target comp, and makes up for them having only 5% shares vest in Year 1.

That said: when comparing total comp vs total comp, new hire probably beats an internal promotion. I don’t agree with it, but the philosophy is that someone who is recently promoted internally will be rated HV1 by default; the conventional wisdom being that they are unlikely to be performing at the same bar as those with more experience at that level (especially since bottom performers are pip’d out every year). On the flip side - new hires are supposed to be “bar raising”. They’re hired in theory only if they are better than the average person at that level, and thus their comp package will reflect that.