Between me and two friends who are all early in our careers, we’ve had very difficult times getting companies to move on salary. This was in SF, all within in the last 6 months.

On the other hand, all three companies increased our starting bonus substantially with hardly a fight.

For two of us the reasons were more or less “you’re already at the top of your salary band” and for the last the reason was they pay all new grads the same (only one of us is a new grad).